Hi Jason ...

First things first ...

Try not to beat yourself up with those old, tired admonitions ...

"If I can do it now why couldn't I do it before ?!"
Frankly Jason ... who cares!

Actually Jason ... you should.
Turned around it's saying ...
"If I couldn't do it before what makes me think I can do it now!"

Those are 2 things you absolutely do not need hanging over your head.
Yesterday, Jason ... that was yesterday.

Today is all you should care about.

You haven't told us what your life situation is, or what support system you may already have in place.
These 2 points are critical for your success, and unfortunately are seriously affected by such things as your physical location and the resources available to you, including financial ones.

So may I suggest a good way to start?

Prove to yourself that you are dead serious about it.

Pound that pavement ... bang on those doors ... make phone calls and explore internet resources until you have a headache! ... and most of all ... have a doctor ... and if you can ... a therapist.
Both of those are invaluable sources of what may be available to you in the community where you live.

example : The nurse in my Doctor's office found this site for me.
You never know who or where something of immense value can be found.

Explore anything and everything that is available for you to use ...
doing something like this alone is possible ... but VERY much harder than with people who know how to attack each aspect of your goal ... and to keep you out of harms way. Like hurting yourself or wasting time and effort that are not best suited to your needs ... therefore robbing you of what you need most ... confidence, determination, and a sense of accomplishment leading to actual success.
The more connections you make the better chance you have of finding what you need to address
BOTH your food/weight/exercise issues ... and your abuse.

So ... make that first definitive step ...
go after this with everything you've got ...
and get everything you can from anywhere you can find it ...

to help yourself ...

Good luck Jason.
Experience is a brutal teacher.