Not sure when to take birth control...

Hello, everyone. Here is the current situation: i am 29 days late. I took 2 pregnancy tests- one a week late from my predicted period date and another one the following week. Both were negative according to the digital test. I was still not convinced, so i went to Planned Parenthood this Monday (yesterday) to take a test and it was still negative. The nurse recommended that I should take birth control to jump start my period, but my friend said that I should wait longer until my period starts. My question is, what should I do then? I feel conflicted. Thank you on advance!