Can PCOS occur suddenly?

I’m 18 and got my period at 12 and I’ve had pretty normal periods, (bad cramps on the first days, cycle last around 25-30 days, not many pms symptoms). For the last four-five periods, they have been very abnormal. My cycle is now 40-45 days long, I get cramps during my cycle rather than just in my period, I’ve been experiencing baldness along my hairline, I’ve had acne forever so there’s no change, and I keep bloating ALL the time. I have so much gas and indigestion. I used to NEVER gain weight and now I’ve gained seven pounds (which is a lot for a 5’1 girl). My pelvic region is also swollen sometimes. Could I possibly have PCOS? I’m going to a doctor but I want opinions first