Hello. I have very regular periods. Usually start on the 11-12 of each month.

Today I am about 4 days late. I tested 2 days ago at 2 days late and got a negative. Is it possible that it was just still too early to test positive ? Had this happened to anyone, but turn test at a later date and got a positive? Any input?

And I did ovulate at my normal time. Confirmed by opk and cm