You know, there have been in history lots of people in your position, even prophets of God. Elijah was suicidal at one point, you know. The way God responded to him was so kind and wonderful; He gave him nourishing food, water, let him take a nap, had him eat again, then sent him out on a long walk, with a hike and maybe some rock climbing towards the end. Then God let His depressed prophet know that He isn't only present in great and magnificent displays of omnipotent power, but that He is also a still, small voice, ready to talk, and ready to listen. Then He led Elijah through some cognitive-behavioral therapy, and finally gave him a purpose. Elijah, the man who prayed for God to kill him, eventually was translated to heaven without ever seeing death. It's an incredible story, and one that you can find in 1 Kings 19.
Another powerful story of someone that we human beings would consider a lost cause is that of Manasseh, king of Judah. Manasseh was the single worst king to ever rule over God's people. He massacred thousands of prophets and followers of God, including the prophet Isaiah - yes, the one who wrote the book of the Bible - through some pretty brutal methods that would have made the Spanish Inquisition think twice. Eventually, he was captured by Assyrians, and dragged off to a foreign prison with hooks in his flesh. Languishing in the prison, Manasseh repented of the evil that he had done. Do you know what God did for him?
God forgave him.
Not only that, but God also freed him from prison and sent him back home.
Even more than this, God also placed him back on the throne of Judah!
Beyond this, God also allowed Manasseh to be the longest-reigning monarch of His people, with a reign that lasted fifty years.
All this for a man who committed crimes that Hitler would have been proud of.
The very fact that you feel so far from God indicates twofold that you are nearer to Him now than you have been before; firstly, because you see how sinful and weak you are, and secondly because the devil is trying desperately to tell you lies about how God will not be there for you, and that He will not hear.
I want to say this again: The idea that God does not listen to you, or that He will not, and the idea that you are a lost cause, are both lies. LIES.
Do not trust your feelings. Jesus promised that He would never turn away anyone who comes to Him. You realize that you are weak and sinful, and that you can never reach the high standards of the law. This is true, but it is no reason to abandon God, because He already knows that! God knew that you could never reach the standards of the law on your own, so He provided Jesus, who did meet the standard, as a substitute. Jesus died on the cross as your substitute, and lived a perfect life as your substitute. We are told that Jesus died for us even when we were His enemies!!
I can't promise that life will get better, because Jesus didn't promise that, either. What Jesus did promise was peace in the midst of trials, encouragement that He has experienced the very worst that the devil and the world could ever throw at anyone (and that He would give us the strength to face whatever comes our way as a result), and power to overcome sin and Satan and live a victorious life in Jesus!
You say,
> I don’t have a purpose, there isn’t a plan.
That's not true. That's a lie borne from the darkest pits of hell.
God declares,
>For I know the thoughts that I think toward you, says the LORD, thoughts of peace and not of evil, to give you a future and a hope.
Jer. 29:11 NKJV.
And we know that He isn't lying, because He can't lie:
>That by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us:
Heb. 6:18, KJV.
I highly recommend this website; it is a fantastic program for helping folks with depression and anxiety, and it is a Bible-based program, too! I also strongly recommend you go to a Bible-based, Christian counselor, if you can. If you can't right now, then I highly recommend you do it as soon as you are able. Counseling is a very good idea for pretty much everyone.
For an understanding of how to come closer to Jesus, I can do no better than to recommend this book and this book. The first one is free and can be read online. The other is not free, but there is an ebook version. Both of these really helped me when I was a baby Christian, struggling with depression, anxiety, and legalism.
I'm also working on a book/YouTube series on depression, focusing on the experience of Elijah. It isn't available yet, of course, but I highly recommend that you check out 1 Kings 19!
Your struggle with this is valid. Overcoming this is not about strength. You need healing, and that is something that only God can give you.
God cares about your mental health and well being. The fact that you are dealing with these things is incredibly painful to Him.
If you need someone to talk to, feel free to reach out to me. I may not always be the best person for listening (for which I apologize in advance, though I do try my best), but I have a lot of knowledge about practical ways for overcoming depression and anxiety (in addition to proper mental healthcare), and I also may be able to help you with any theological questions you may have.
God bless you on your journey! You don't have to live life like this! Jesus is calling to you to commit yourself to Him! He gives peace like no other ever can, and rest in His arms is sweeter than the grave could ever give you! Yield to His pleading; I can guarantee that He is waiting eagerly to welcome you in with a celebration grander than any human mind could ever comprehend!