How come I can't remember anything lately?

I’m 22 and lately I’ve been having a really hard time remembering things. I’ll think of something then a few seconds later completely forget. Then a few minutes I’ll remember. This doesn’t happen a lot, in fact I’d say maybe a few times a year. But lately (as in the past month and a half) I’ve been having trouble remember things. Not big things, just forgetting for a second. I don’t know why it’s happening. It’s annoying. I just started taking fish oil that I bought from GNC (1500MG) and I hope it’ll work. I’ve heard taking fish oil is good for memory and the brain. It’s annoying and I don’t know what it could be, help :(