please may I have some advice

My BF and I had sex on the 18th November and he finished in me. I am on the pill. I ended my period on the 12th November. However I didn't take my pills in sequence. I took the pill as if I'm in week two right after my period. Am I still safe or am have I made a mistake? I had been on the pill for a month in a half before this happened. My breasts are always tender due to the pill but I haven't had any other symptoms. But I still believe if it's the worst thing then it's still to early, yes? I really hope I'm not pregnant!