Help!!

For the last year or so my period was between 5-7 days! I get it faithfully every month within a couple days to a week from where I had it last. My last “period” I had was literally a day and I spotted. It’s very unusual for me because my period is usually heavy. I’m now starting to get a little nauseous in the mornings. I really don’t think I’m pregnant because my boyfriend & I use condoms and he makes sure they don’t break FAITHFULLY (it’s one of his biggest fears lol). Any idea on what this could be? I really don’t wanna buy a pregnancy test if it could be something else lol (btw I’m like 2 weeks late)