Chances?

From what this app says my period is a few days late. My ex and I were having unprotected sex but I have always been on bc. He had an injury when he was over seas that cause him to have surgery so his sperm count and now pretty low. I have read some where that you can sometimes tell you’re pregnant by checking your cervix. I did that and it’s up pretty high and is sort of firm and closed. So I really don’t know what that means. I feel like it’s definitely to early to buy a test. I just want some opinions on what everyone thinks.