Could I be having a "mega-period" and could it cause these symptoms?

My surgery in January really scrambled up my menstrual cycle and I hadn’t had a period since then, until today.

By missing my period a few months in a row, could I have had any sort of “build up” of hormones causing my current period to be more intense than usual? I don’t know if this happens, but it seems like it could.

If I am having a “mega-period” lol could that cause me to have PMS symptoms way far in advance? My appetite has been extremely poor for a couple of weeks now, I’ve been waking up with headaches for the past several days, and I’ve been very low on energy for the last several days too. Is it possible for PMS to begin a few weeks before your period, especially if it’s the first one you’ve had in a while?