What is TOO paranoid, when it comes to the chances of pregnancy?

I think a lot of the time it’s complete paranoia for us girls. I’m certainly paranoid right now - am normally not all that wild, but had sex (protected) with 2 different guys in the space of a week… though the 2nd one was inside me for like a split second before we put a condom on. Not the best idea tbh, as I’m not on any pill, but there we go. As far as I’m aware, none of the condoms ripped or anything, (guy 1, as I shall call him, was actually VERY careful about making sure condoms were on right). Anyway, so now, just because my period hasn’t turned up yet I’m freaking out! Logically speaking, of course, the chances are slim: My ‘day 1’ varies wildly, spanning a good fortnight (am currently towards the back end of that though); If I think about the stats involved in pregnancy in the 1st place, it’s only 1 in how many?? ooh, right just looked it up & here we go: a regularly sexually active woman who is not using any form of birth control has an 11 percent chance of conceiving each month. condoms are supposedly 97% effective, but it’s said that this drops to 85% when we account for human error - aka, being a bit rough when unwrapping it, or if it rolls up when you’re having sex, or…well any number of things really! It’s not exact, & it never will be. *Therefore, it stands to reason that even with the 12% drop, my chances of being pregnant are around 1.65% (without the drop, it’s around 0.33%) This is if I disregard the fact that you can get pregnant off pre-cum. Which blows these calculations outta the water. ROUND ARGUMENT, you see! As long as the CHANCE is above 0.00000%, I’m gonna panic. And this is what we’re up against… statistics that we figure out to fit to our situation, & end up so bloody paranoid about the whole issue that our periods are probably only late due to the immense stress we are putting ourselves under! And in the meantime… our guys are wondering round oblivious & blissfully happy. I’m waiting and hoping for the best for a few more days… then taking a test. What makes it worse is that I’ve moved home for the summer & my mum still thinks I’m a virgin…& is totally against casual sex. Oh dear, I wasn’t wishing to disappoint her to this extent before I made it to 20. Anyways, whatever the outcome, I’m gonna sort it out & then see about going on the pill.

Have I just made myself sound insane, or does everyone else worry themselves silly too?!