So, you've made the first step, you've decided to do something. It sounds really simple, but now it's just a case of starting to do it. I don't know much about PCOS, but... I do know that switching to less sugar / carbs is likely going to help. So, approach it from that point with your mother. Try explaining your concern for your health. Maybe you can sit down and plan your meals for the week. If she wants some snack foods for herself, then just pick a cupboard, and ask her to keep it there. We always have chips in the house (used to be I could eat a big bag in a sitting), but they're in a cupboard I don't need to open on a daily basis. That helped a lot at the start. If you don't cook much, now is as good a time as any. I honestly haven't given up any of the meals I enjoy. I've just found ways to make them lighter and/or healthier.
On the gym... just go. It's not as scary as you think. Find an activity you like, and that makes it easier. I'm still not a fan of cardio (walking for me usually), but I love lifting weights.
It's all about making small changes. I was slowly gaining weight I'd already lost last fall, also unemployed. Well, in December I decided that I'd had enough and found it easier to lose weight when I wasn't working. I mean, I could set my own hours, cook everything I needed, etc. Heck, I wish I'd got my act together earlier, as I'd be further along. Now I'm back in school and never seem to have any time. However, those good habits I started are easier to keep up. I took time today to bake 4 (9x13) pans of my grab and go snack foods. These are higher protein bars/squares that I keep in the freezer and take with me during the week for snacks. I was willing to give up some time this morning (and again in the afternoon) to make what will likely be 6 - 8 weeks worth of my new 'junk food'.
Anyway, that's a lot of rambling to just say welcome. You'll get as much help as you want here. I'm not around much myself (time issues), but feel free to join in the weekly threads. They move pretty fast, but they're very friendly.