Early to Late Menstrual cycles

Lexus
Okay so I'm trying to to have a panic attack because I'm late on my cycle. This happened once before in 2011 and I cried everyday until my cycle came because I thought I was pregnant from being late. Now those same feelings are trying to rise. 
Ok so the last three cycles I was like 3 to 4 days early and this time....specifically today I am a day late and I don't want to have to worry about pregnancy. 
How late can you be on your cycle without having to worry about pregnancy? 
Every time I've had sex my boyfriend and I used a condom and he pulls out each time. I think it may have been one time he didn't pull out but we still used a condom. And that was approximately two weeks ago. Should I be worried about pregnancy? Am I overreacting???