I’m 20 days delayed. Am i pregnant?

I know in myself that I am not pregnant. I mean if I am, I’m sure i’ll know it in some way but I’m not feeling well these past few days. Lower back pain, nausea but without vomiting, swollen breast. All of these are symptoms of early pregnancy. What do you think? Am i pregnant or not? My boyfriend wont be back til’ next month and I’m scared to use pt by myself but i dont wanna wait that long to confirm it. Help me out please :(