How do you prevent anxiety spikes. Overreactions? (For those who suffer from anxiety related issues)

[Locut0s]

One of my big problems is my immediate reaction when faced with something new or challenging is that I get this huge anxiety spike. I get this not just with social situations, where I'm worst, but with anything where I don't feel confident or where something new comes up that I'm not expecting. The really annoying thing is that more often than not the solution is very simple and afterwards I get this HUGE sense of relief that the problem is solved.

I'll give you an example. I'm studying for final exams now and I run into something that I feel I should know but don't know quite well enough. My immediate feeling is one of panic and hopelessness. "I'm going to fail this, how can I not even know this right now!?" But, pushing through that and sitting down to look at the issue for 20-30 mins I realize I know all of it, I was just a bit rusty. Or I didn't know it but was able to work it out fine in that 20 mins. And again, I get this HUGE sense of relief.

The question is how do you prevent that spike of anxiety in the first place. Because truth be told I can't continue living like this. The constant anxiety and relief roller coaster, not to mention my horrible depression, is tearing me apart emotionally.