I Need some help/advice

I am really struggling lately. Yesterday I skipped work and class because I was feeling down and didn't want to do anything. It made me upset because I felt like I was letting myself down and my boss down by not going in.

I am continuing to really struggle today. I am a student and I actually made it to class. But then I got all of this anxiety about going into work after. I had a doctors appointment which ended up making me late, and I got really upset in the appointment and was not fit to go into work after.

I worked at this place last summer as an internship and stopped in August to go back to school. A couple weeks ago my boss emailed me and asked if I could come in and cover for me while she was away for a few weeks, and I said yes. But i've been regretting the decision ever since. School has been pilling up, I have a few side jobs now that are giving me a lot of work and filling in for her is just stressing me out now. But it's making me really upset because I feel like i'm letting her down, and i'm just making excuses even though I know in my heart that it's just going to be too much for me right now!

I have suffered from depressions for a long time now, and I haven't felt stable for a while now. This is just making it worse, and its making me really upset. I just don't know what to do....

Is there any chance you could tell her that you recently gone a lot of unexpected school work and let her know that you can't help out?

Maybe apologise and say you didn't realise they you would have that much school work to do. Just let her know that you have to much going on right now to help out, most people will (hopefully) understand that.