You are NOT overthinking it. It's a common issue with people who are walking the spiritual path to be awakened to their true self. It is during this phase of awakening where you may experience negative entities.
When you are awakening to your true self, you are also presenting a threat to these negative entities. So you spoke of yourself being of Native American heritage and how you are naturally connected to nature and energy vibrations and presents to them a greater vector of threats in the future where you may have abilities to see and identity them out in the open which mature Native American spiritual people can do. And depending on your level of maturity of your innate gifts, you can even with the help of the heavenly beings bind and consume them into the light through certain Native American rituals. So rather then they let you mature to that stage, these negative entities would rather discourage you from developing your full innate spiritual gifts.
This is what you are experiencing now. Now let me share with you what sort of entities you are dealing with. In the spiritual world, there are 4 classes of entities. The 4 classes represents our spiritual bodies; which is the
1, Identity body (realm)
2, Mental body (realm)
3, Emotional body (realm)
4, Physical body (realm)
Each of these bodies have negative entities that exist in these realms can mess with your bodies causing you to experience what you had just described.
So let's start with the entities residing in the identity beings (known also as beings in the Etheric realm). They are very good at projecting an alternative identity of you, by making you suicidal, worthless etc.. They can steal your energy by making you suicidal.
The second class of entities are known as mental beings. As with the name mental, they are good at projecting mental thoughts like someone is watching you, when in fact they may or may not be watching you. Doubts, indecision etc.. Any mental thoughts that are not your thoughts come from them and they can steal your energy by making yourself THINK you are being watched and THINK your bf is your enemy.
The third class of entities are known as emotional beings. These beings project emotions to get you angry and irritable. When you are angry and irritable are when they can steal energy from you.
The last class of entities are known as physical beings or discarnate souls or also known as ghosts. These beings are stuck in the physical realm and they make all kinds of physical phenomenon like moving pots, footsteps and of course, they get you to react with fear. When you react in fear to these physical phenomenon is when these beings can steal your energy.
So basically this explains why you are completely drained. The "off" energy is because these beings vibrate at a much lower vibration than heavenly beings of God. I'm also energy sensitive as well and also, like you, can sense if there are malicious entities in any room or even entities that are possessing a certain world leader or a person. This is a skill that negative entities DO NOT WANT YOU to master for obvious reasons.
So how can you protect yourself from these entities? Well, a valid spiritual path also comes with tools to protect you from attacks from these entities. They are called spiritual protection prayers.
I'll direct you to a book that explains this issue further and see if this resonates with you. But you must use protection prayers to protect you, otherwise they won't stop harassing you. All these entities want is to discourage you to continue on your spiritual path. They can't stop you, but they can slow you down which is what they are doing to you.
Anyhow, here's a book that can help you further..
https://www.amazon.com/Remarkable-Healings-Psychiatrist-Discovers-Unsuspected-ebook/dp/B001VNC8TQ