Very confused !! I need help

Well eve is telling me I'm 4 days late to start my period but I think she's wrong because my last period was longer than usual and it's only been 2 weeks since then. I'm pretty confident I'll start later this week but I have NO discharge!!! And my boobs are very sore and are bigger. I'm pretty sure it's PMS but I just want to make sure . I've been on the pills for 3 months now so I'm not sure if this is a side effect? My periods go on a roller coaster with how regular they are. I need help!!!!!😞😞😞