My other half went through the exact same problem at 1st 10 months later he went from 30 stone to 12.
During that 10 months he made a journal logging each day. What he had done, eaten, how he had felt, what triggered that feeling. From day 1 to the end you could see the struggle to the mind change. Start is always the hardest.
The thoughts and the worry can set you back but baby steps can help out a lot. From him being unable to walk more than 50 metres without breaking a sweat, to him walking 7 miles and wanting more within 10 months is a huge milestone in such a little time.
His journal may give you a point in the right direction and it will be something you can relate with.
https://www.amazon.co.uk/dp/B00RS1HVHY/ref=cm_sw_r_cp_apa_3I.eybPNP6CZM it's free for prime users and we'll worth the read. You won't feel alone.
His twitter is @becauseiwasfat
If anything it's worth a look