Depression

I don't know what to do and I'm scared, I've felt like this before but I'm having really bad episodes now. Yesterday I was feeling fine, it was the first time in two months that I felt relieved and okay but today I wake up feeling exhausted and suicidal. I'm Christian, I believe in God, I pray and I want to feel better but when I don't I feel better I feel like I'm a shame, after all, I'm Christian and God is with me why would I still feel like this? I take therapy at school, once a week but I feel like it's not helping me enough, I can't have an appointment with a psychiatrist, I don't have the money to do so. I don't know what to do.