I am so sad for you, and so sorry you're going through this.
In my area, we have free mental health to people who qualify, as well as free general health insurance. Contact Medicaid in your area and see if you qualify for anything. You’d be surprised, lots of people qualify who never imagined they would.
As for the diet and exercise, the hardest part is getting started. If you make a healthy choice for breakfast, then you’re more likely to make healthy choices all day. Get up in the morning and have something healthy. Like eggs whites, turkey bacon and fruit, or if you’re short on time, a bowl of Special K with skim milk will do. Just make sure you measure the correct portion according to what the box says is a serving size. Pack a lunch for work so you’re less likely to make bad choices throughout the day. Pack lots of fruits, low fat cheeses, salad with olive oil and pepper instead of dressing. There are lots of low-calorie yogurts, and Jello is very good for a sweet tooth since it comes in convenient packs and it is sugar free.
For exercise, just walk. You can even just walk in place in your living room while you watch your favorite show. I have two small kids and a husband who works nights, so I am always home alone with my kids during the week. So I walk, or I jog in place, or do jumping jacks, or whatever while I watch tv, since I can’t go out. It’s an excellent way to start out for someone who is currently not active. If you have cable or satellite, you probably have access to On Demand (Comcast) or something similar. There are free workouts on there, I use them all the time. Or you can even check out workouts on dvd from the library. Also, Jillian Michaels has some really good workouts available for $9 at Walmart. I have the Burn Fat, Boost Metabolism one and its intense. I love it. If you don’t like to work out, I hear Zumba is really fun. It’s like dancing, and there are many dvds for it available, and you can also do that in your living room.
The most important thing, which I need to actually take my own advice on, is to not beat yourself up over a mistake. So you slipped and ate a piece of chocolate cake. Or even half of a chocolate cake. Oh well. Not the end of the world. Just remember how guilty you feel and move on. Promise yourself to remember that feeling the next time you want something that’s bad for you, and do it. Then continue the healthy eating the rest of the day. Just slipping up once or twice doesn’t mean the diet is ruined and it doesn’t mean it’s time to quit. Just brush yourself off and keep going. You deserve to be happy, you deserve to have friends, and if those idiots treated you that badly then you’re way better than them anyway. They were never worth your time, and trust me, you’re better off without them. I’m sure you are an awesome person, and you have a job caring for others so that must mean you’re a good person, and you just need to start loving yourself. You CAN do this. Just keep posting on here and I am sure you’ll have plenty of e-friends in no time. Honestly, the best friends I have in my life are all people I met online anyway.