So, I have a very weird pattern with my self esteem. There are days when I feel my personality shining, and my interactions with people goes very naturally and easygoing. I feel my best in these days. But after some time, I start feeling very poorly of myself, and that's when the bad days come. I start feeling self conscious about every little thing I say, negative thoughts come into my mind, telling me that I'm worthless, and that my personality is shitty, even if I'm not doing nothing wrong at all, it's a whole social anxiety hell, and it's concerning me, because I have the good days, but then, after a few weeks, I get feeling horrible again, and in these days, there's nothing that can makes me feel better, really, nothing, I feel like crap no matter what. And yes, in these days I try to force myself to be positive, but it's impossible, it seems like something blocks me to act naturally and easygoing, like a lump in my throat. 
 I hate this loop, and I don't why it's been this way. It's nothing new, I have this pattern since two years ago, and it's going so bad to the point that, when I'm in the good days, I feel scared and anxious about the bad days that will come. This pattern is pretty random, there are no certain time to feel this. It's something I can't control,  like I said, it's like something that blocks me to be normal and feel ok with myself. What's this exactly? I don't understand what's this. Has someone here felt something similar?