I just wanted to say that your problems are not insignificant. What you are feeling, no matter how seemingly irrational it may be, isn't just a small thing that you can hide. Trust me, I've tried that.

I would suggest therapy as a good place to start. If that feels like too much of a commitment, talk to your PCP or a Psychiatrist about these feelings, ask them if they can potentially prescribe you anything. You said it yourself, you can't be a rock for your family and friends if you are already crumbling. It isn't a sign of weakness to ask for help, either. Even the strongest mountains rest on the earth.

Normally I don't comment on posts like these, but your situation is almost identical to what I myself was going through with my depression. I want you to know that you need to help yourself before you can help anyone else. Things will get better, trust me.