You were absolutely right; bottling your emotions all day and putting on a happy face does lead to seemingly uncontrollable bouts of those emotions coming out later. While I do understand that it wouldn't exactly be the best thing for you to let it out during the middle of a class or exam, I also know that the longer you keep it bottled in, the worse it will get. Personally I think that letting it out when you do get home is a better alternative than keeping it bottled as long as you possibly can. Something that I've found that helps me with that, is walking. You don’t have to have a destination, just go out walking. If that’s not a feasible option then maybe open a window and take a nap near it.

As for feeling like you come off as spoiled and unappreciative; people who don’t understand depression and what it’s like might very well think that is the case, however it is usually not. In your case (from what I've read), I don’t think you’re spoiled or unappreciative at all. I think you’re giving yourself a reason not to open up to anybody and a reason to keep it all inside. You need to open up to someone and I am glad that you've done it here. Maybe someone else who is better at helping with these things than I am can offer some solid advice.

The feeling like you’re not pretty enough – just stop there. You do not have to please anybody but yourself. If anyone is telling you that you’re not pretty or thin enough for them (with exception for medical professionals who see health problems directly related to your weight), then they do not need to be a part of your life. Not only is it an incredibly shallow thing for someone to think, it’s very demeaning and does wonders in shattering self-esteem for someone to hear. If you feel like you need to change your appearance to suit your mother, then I am sorry but your mother is not worth your time.

If you are in America there are mental health facilities everywhere that work on a sliding scale with your income. I was seeing a therapist and psychiatrist 2 years ago when I was living with my mother whose monthly visits only cost me $3.00 (not including prescription prices which vary based on where you get them filled). Yes, three dollars. While it wasn't the best care, I did get the medication I needed, I got someone who was willing to listen to me and offer advice that was quite often great advice, and at the time I felt better about everything as a whole.

You said that you weren't sure if your parents were willing to help you get one or not; if they aren't then it is always possible that you can look into local bus routes and prices to get yourself around. If that fails, then perhaps ask someone else that you know to take you. If you are under 18, however, you will face a lot of issues with this. If you are, you might want to send your parents to websites like this one in an effort to try and get her to understand that this is a very real thing and that help is needed.

I hope this helped in some way.