Recently (in the past 2-3 weeks) I have been experiencing moments of sudden anxiety and depression. Like, I'm minding my everyday routines, and all of a sudden, with no apparent cause, my thoughts start racing and I have to stop whatever it is I'm doing. Minutes later, I feel like I'm in a very very bad mood and I just crawl in my bed and lie there for minutes or maybe more, having thoughts like "What is this? What's wrong with me?" or the worse "What am I doing with my life?" or simply start questioning recent decisions, overthinking. During this moments, my pulse is higher than usual. But what's even weirder is that they simply vanish. Suddenly, my dark thoughts are just gone and I feel fine. What could this be? I've never seen a psychologist because, well, before this, I've been able to cope with my (I consider them small) personal problems on my own. But I am freaking out right now. Can anybody help me?