Late period - exam stress?

I’m 10 days late for my period which has never happened before. I was on the pill for 3 years but had to come off a few months ago due to problems with my hormones.

I’m supposed to be getting a coil on Tuesday but they won’t do it if they know I haven’t had my period!

I’ve very recently finished my exams so I’ve been super stressed.

I’ve been having sex but have been extra careful with condoms and I’ve also taken two pregnancy tests which have both come back negative. Any advice? 😭