Pregnant or not??

christinya
I been ttc and I recently missed my period and took a test but it was negative I think it was too early because I have lower back pain, nausea every afternoon, always in the bathroom and it's embarassing but can't keep anything in like I got the runs. I wonder if I'm pregnant now my nipples are erected what to do because if I am I would be 5 weeks.. What to do?