Someone please help

Okay for the last few days ive been waking up sick super nauseous ive taken 2 pregnancy test they both say negative. I used 1st response. But my period is supposedly latw by 15 days +. I dont have time to go to the doctor bc my only off days are the weekends now. I honestly think im pregnant. Should i wait a few days and take another. Try a different pregnancy test or what. My stomachs been hurting alot too on different sides. I tried to go urgnt car it wss 5he only place still open after my job but they diddnt accept my insurance or it was gone be 100$ up front . what shpuld i do!!!