2 days ago I was feeling great. I was pretty happy, internally sound. For no reason tonight I just feel so down

It’s pissing me off why this shit happens, like I can’t even retrace what went so wrong all of a sudden I’m feeling like this.

It always happens to me, One week just feeling fine, feeling good about myself actually then all of a sudden this splurge of feeling sad. Then the feeling snowballs and I feel like crap for the next week

I really don’t get it, I’ve tried going off social media, I thought it was instagram giving me self esteem issues. I tried working out, I got a girl friend, multiple. But nothing, same thing keeps happening for no apparent reason

Is there any way I can find out what’s wrong with me?