There is a such thing as too many roleplays. Keep that in mind. Also keep in mind that if you feel too stressed, tell your roleplay partners and take a break! Nobody will judge you for it, I've been in the same situation.
Ask for advice from others on this site. I've been lurking for a while, and I've seen that most are pretty kind.
Keep your character flaws logical, and make sure that flaws and positives are at around the same number. Nobody is perfect, but everybody has tons of good things about them, even if they don't know it just yet.
And always stay positive. If you don't, it'll leak into your writing and the character's actions will not fit your character at all. Maybe it might fit the character because of what may be going on in the RP, but that's...kinda sorta rare. If you're feeling down, take a short (maybe long) break to get yourself together.
Have a good time.