I'm late

Katieann
So I'm late. By 3 days. I've been experiencing nausea-sometimes strong, sometimes barely there for roughly a week and a half now. My nipples have started to feel sore just a couple days ago and just yesterday my breasts have been tender on and off including today. I've also been more sluggish and fatigued since a week ago-in fact I've been sleeping almost half the day away most of the time or require several naps throughout the day. I've also had frequent headaches that just do not go away. Like at all. And I've had slight cramping too on and off since 7-14 dpo. At 12 dpo I went to universal studios and for roughly 30 minutes while on the tour, my stomach and my back were in utter pain. But then it just went away. I seriously thought I was going to start AF but I'm now 3 days late. However I have irregular periods but my P.D app has always been spot on with them and it said I was supposed to start the 10th but Glow said the 14th and Ovia said the 15th and still nothing. My lower back hurts more than usual but idk what that could mean since I had back problems before and am actually going into physical therapy for it soon. I also had what I thought might've been a sign of implantation happen on 8-9 dpo because I had watery discharge spots on my underwear all throughout those two days and then it was just gone. But I took a test yesterday and BFN. So. . . What do I do? Any advice? Any comments or suggestions? I'm not stressed-I actually suffer from anxiety but I have meds for that-so im pretty chill. I'm just. Confused?