Plan B missed Period 2nd month

Okay so here's my situation. Last month I took a plan B pill and started my period on time but it was really light. This is the 2nd month after taking the pill and my period is 5 days late. I started working out this month and have been a bit stressed and I've taken 2 pregnancy tests and they both say negative. My boobs are sore and I've been breaking out and craving things But still no period. Could I still be pregnant? Should I go to the doctor and find out or just wait it out?? Has anyone ever had the plan b pill mess up your period not the first but the 2nd month??