Explain please !!

So I was supposed to start my period yesterday but I have not started yet. I’ve been experiencing some symptoms like headache, mild cramps in lower abdomen, hot flashes, and back pain. It’s been off and on the past few days, and I thought that it could be pms but idk. I also have had a lot of white discharge. Please help explain!! I also took plan b earlier this month so I know it can delay periods but I’m stressed I haven’t had one yet this month