Nervous I'm pregnant

Low key freaking out. Let's walk through this: I am a rather anxious/paranoid person to begin with but work to keep it under control with medication. I have recently started a new medication. My boyfriend and I have sex with condoms and only once without in the last three weeks, relying on the pull out method. My period is two and a half weeks late. I have been known to occasionally skip a period or two is succession.  I am confident I'm not really pregnant but I keep over thinking and freaking myself out.