might be pregnant please help

So I started my pill pack January 20 (sunday) and my boyfriend graduated from boot camp January 25 and we had sex (we always have unprotected sex we’ve been together for 3 years) and I used to have the rod but I got it out in December while he was gone. Anyways I did miss 2 days while he was here and we did have sex but I took double for the next 2 days afterwards to catch up. He’s gone now I’m not having sex but I’m still taking the pills each day. I’m on the last week where you’re supposed to get your period and mine still hasn’t come...Would it be too soon to take a test? how long should I wait? I’m stressing because my 20th birthday is this month on the 25th and my friends and family want to drink but if I’m pregnant I’m not going to do that.

Please help