When can I test?

So i've been on the POP pill for the last 18 months and this stopped my periods. 2 weeks ago me and my other half decided to start TTC so i stopped taking my pill. Since then I have just been waiting for AF and for my body to get back into a normal cycle. This is where this takes a randon turn 😂 so ive had my tongue pierced for 4 years now but the last 5 days its become really swollen and today ive woke up with a clear infection, so i've been speaking to my body piercer (he's a family member so im close with him and have loads of piercings) and when ive shown him he has told me to check if im pregnant as an infection after this long can be occur due to being pregnant. Now I know it would be very unlikey that i am already pregnant in 2 weeks of stopping my pill but we can't help but wonder. Im now just wondering when I would be able to take a test to find out for sure?