Is it just me or has anyone experienced going a while without a period and not being pregnant? I am so lost right now trying to figure out what is going on and I’m wondering if I’m the only one!!

I go to the ob in a few days to address my issues but I’m rlly nervous that I’m pregnant (not in my plans rn!!) can someone help or give advice?

Side note: I did recently start a night shift job for the first time haven’t been getting much sleep compared to what I’m used to. I read that hormones and everything can change drastically because of not getting sleep but it’s still confusing to me. Please helpppp!! :))