could I be pregnant or am I paranoid?

Okay so I haven't been on birth control for 3 weeks due to my doctor wanting to switch me to a different brand then insurance wouldn't approve of it. Long story short she said that if my boyfriend and I want to have sex to use additional protection. (We usually use birth control and Trojan condoms anyway) we decided to have sex (only once) within the 3 weeks. The condom broke. We thought about plan B, but I had a bad reaction to it when I took it about 2 years ago.. I'm supposed to get back on birth control on Monday 3/13 and the condom broke Monday 3/6. I probably sound paranoid but should I take a test on Monday? Should I wait another week so the test is more accurate? If I start the birth control back up will it harm the baby if I'm pregnant? My doctors appointment isn't till3/20 and they can't get me in any sooner. Is there a test that I can take to find out early? Now I'm a worry wart over this.. ☹️