*hugs*

You're going through a rough time. Lots of stress from many different sources, and even if none of the issues alone seem major, combined they drag you down. I'm experiencing something similar right now. Hang in there. This too shall pass. As for your 'friend', don't bother with her for a little while. If she cares enough to explain why she's upset when she knows you don't get it, she'll make contact and tell you. At the moment she's acting unreasonably, and there's no sense letting her become another stressor - Drop her like a sack of bricks until she gets her head sorted out again.

Find a new hobby, or something amusing to do in your free time that'll take your full attention, so you don't have too much time to think about life.

Here's hoping things get better for you soon. You'll do just fine.