Is This Normal?

I'm sorry if this has been asked a lot, I just don't know if its normal or not.

I'm 22, sexually active(not very much, my fiance is living in another country, haha)but we do use condoms, so I'm not worried about STDs or anything.

I've been notiving over the last year or so before I get my period I get a white/off white discharge that sometimes may have the slightest hint of green to it. Not every month, just sometimes. It usually has a slight smell of like...yeast. But there are no burny/itchy feelings like a yest infections. It only happens before my period, but because it has a slight yeasty smell and sometimes looks like it might have a little green to it(its really subtle, maybe my eye sighs just going weird lol) I'm just curious if anyone gets the same/knows of some reasons it would cause the faint yeasty smell and stuff.

I have looked it up, but it seems like everything points to std, and talks about fishy smell and stuff, which I don't have.