Overthinking is a killer

So this was my third month TTC. I got AF yday. Obviously feeling as low as hell. Friends are all messaging me telling me that they're pregnant and I'm here wishing to be the next one. My drawback is overthinking. I just don't stop. I can't help it. How can someone who gets their period on the 28th of every month, gets positive OPKs, doesn't smoke, doesn't drink and is healthy not get pregnant immediately? I might sound ridiculous to some of you but it's just how I'm feeling. I will be turning 34 next month so it panics me. I was on the pill for 4 years and stopped in in May 2020... I doubt the pill is still in my system after a year. #feelinghelpless