help!☹️️

Hey everyone! So for the past couple months I've become regularly sexually activate when before it was few and far in between. Ever since my periods have been coming later & later, I've been over a week late most months, which is now normal. But I didn't have a period at all September, I was supposed to have it the very last week of September but I still haven't gotten it, I'm unable to take birth control for medical reasons. But we've been using condoms. I guess I'm just looking for some advice! I'm stressing every month that I'm pregnant due to a late period and kids really aren't an option right now. I'm stressing that I didn't have on in September but every time I go to take a test I start the next day so I don't what to think or do. ☹️️