7 days late...

Becca

Well I am 7 days late on my period and I've tested at 1 day late and 3 days late and both said negative(both was dollar tree brand) I was recently told not to use them. Normally when I am late I just have sex and I start within a day. Well I've had sex alot and not even a tiny bit of red. I was told stress can delay a period but in all honesty I'm not really all that stressed. I mean i am but nothing out of the ordinary. SO my question is, Should I test with a walmart brand test or should I assume I am not and go about my day? I have had weird signs also like I had major back/sife pains for a week before my expected period and last night till today I have had diarrhea. I dont feel sick or anything like that but I just dont know. I'm kind of like.......Can I please either start or have a positive test please. I HATE not knowing. TIA to anyone with kind words or advice.