Hugs to you. My drug of choice was bourbon, vodka, scotch, beer, wine ..... etc.
Then I got talked to by my parents and partner and asked why I was killing myself.
Queue up, I had to have a male GP. I could not have a female doctor because I was a man (Texas) ... So got the therapy to handle the basic exam including a prostate examination (think about that being raped and holding it in for 22 plus years).
I got through that and I fought hard and back on everything, including my disdain for feminists (I became one), and everything else.
Now I am repairing my body from the damage of decades.
The only drugs I take now are for my allergies and for the side effects of the drugs, and now I am fighting back.
You can do it. I am cheering for you. I know if my current relationship ends (I blame myself for the failures). I know whomever wants to partner up with me will have a strong and willful partner to "ride or die".
So look at walking and exercise like the end goal is getting the partner of your dreams. It can be both loving yourself on the inside, and finding someone worthy enough of that same warrior within.
As for size ... all I care for is that my partner is healthy and happy and has the energy to do anything and everything with me. I was an ex-athlete so I know the one end of the scale, and now I am fighting back on the opposite side.
As for intimacy partners, size isn't everything or anything. Give me a person with a big heart, a big soul and a big appetite for intimacy and I am totally ok with someone with curves and larger. Because you know what .... as I am a large guy, a woman of size has a better chance against me then a twig. :)