I just want to wish you the best of luck Whatta!
While I've never been "big" I definitely know how it feels to realize you just can't do what you used to be able to, especially the riding.
I gained 30 lbs after I got married after being the same size and weight since about 7th grade. It was a combination of getting a new job (went to desk job after working at a dairy feeding, cleaning stalls, and herding cows to the parlor. VERY active) and hubby being a picky eater, so I picked up his bad eating habits. It didn't physically look
like I had gained, but I could feel it. I was always winded, my strength was gone, and I had gone up a size in pants. Riding had gotten to be a chore. I was already wore out after saddling up, and plumb exhausted after I was done. I had also developed stomach issues.
I was tired of feeling like crap. But I HATED exercising. When I thought of exercising, I thought of running and sit ups... yuck! I also couldn't figure out how to change my diet, because I didn't want to make two meals a night, one for me, one for hubby. I grew up on lots of fruits and veggies and made from scratch meals, and he didn't.
I've been blessed recently to have an opportunity to work at an evening fitness studio in town. I check people into the classes for about 15 minutes at either 8:00 or 9:00 depending on the day, and in exchange I get to do the classes free of charge. So for 4 days a week I do either Kickboxing, Zumba, or Yoga. I love that way
more than running haha. I've also figured out I can get in my healthy meal at work, so I've been doing lots of meal prep there. I try to drink nothing but water, but... uh... once a month I tend to give in and have a Coke or two...
I've only lost about 5 lbs and sit at about 155lbs, but that's ok. I feel good. I feel strong. I look freaking buff. My stomach rarely hurts. My balance is coming back. And riding doesn't wear me out.
I still have a long ways to go as far as my eating. Hubby also realized recently that he's gotten a bit large and wants to make a change too, so hopefully with us both in the same mind set that will get easier.
Again, I wish you the best of luck, and look forward to watching your progress. You have many people here who will be rooting for you!