Pregnancy vs PMS symptoms?

My period was supposed to start today according to the app and it never showed up. I’ve been ttc for months now and found out i have PCOS. I have had swollen, tender breasts, eating more than usual, tightness in my lower back/pelvis area, super sleepy, cry at everything, diarrhea, heartburn like crazy. I usually have some terrible cramps but not like this, it’s a tighter feeling. I took a test with FMU today but it was negative. Is there even any way... Could I be pregnant?