I don’t know what to think?? Please help !

I’m on birth control because I have irregular periods and I have polycystic ovarian syndrome. From mid December to late March I haven’t had a period. I believe my period finally came at the end of March but it was longer than usual. It was 9 days versus the 4 day period I had in November. I have also noticed that I have gained 6-7 pounds between January (127 lbs) and weighing myself today (133.2-134.8). I took a pregnancy test two weeks ago and got two negatives but I am still concerned whether or not the sudden weight gain is just me needing to work out more and watch my diet or if it’s pregnancy weight. My mom has even commented that I’m “getting thick” and my jeans feel tighter than they did two weeks ago. Should I be worried?