Can this be an early sign of pregnancy? (Has anyone had this before)

My periods are always regular. I get it every month same time and it lasts 7 days of bleeding. Day 1-3 is always HEAVY and i always have to change my tampon every hour or 2 or else it will bleed thru. Well, this time around, i bled “heavy” for only 1 day?? Just the first day. No leaks onto my pads at night, no soaking a tampon fully. Im confused. Its day 5 of my period, and theres nothing on my tampon. Yesterday, day 4 there was bareeely any blood, it looked like spotting i usually have on day 7. Its like my period ended super early. This has never ever happened before. Nothing has changed with stress, hormones, or birth control. And TMI but i almost vomited i had to run to the trash after deep throating my bfs dick the other day (never happened before) also today i felt nauseous for a second because i felt mucus in the back of my throat?? What could this be besides pregnancy or a random irregular period? This is very unusual for me