I’m no expert at cheering people up, and I don’t know too much about the situation, but hey, I’ll give it a shot!
Please hang in there, Katie. <3 I'm 100% sure that there are many, many people (offline and online, like myself!) who care about you very, very much and who are deeply worried about you and wish for your happiness. =(
I know that things can start looking up for you—my sister has been suffering from depression for over three years, and like you, her progress has been going up and down. She’s been getting better at it though, I think in the longterm—she went to a therapist, but she didn’t enjoy it—so my parents decided to just have her talk about things between her and them, or someone else she felt close to. And I think that really helped. <3 That method may or may not be something that'd help you too, but it's worth a try. =)
Just remember that if you want to talk to anyone (again, offline or online), you should never hesitate to ask, because in the end, it may be able to help you. =)