How long until I should worry

My SO and I had protected sex (condom only) often during the whole week I ovulated. At one point post sex, one of the condoms looked funny so we checked it under the sink. My SO didn’t see any holes, I thought I saw a very slow drip, but it could have been water running off the outside of the condom. Either way, unlike most periods I have had slight cramps off and on since two weeks before my period was due to come. I’m three days late for my period with clear/ white discharge, my nipples are painful to touch (not one of my normal symptoms), and I’ve had headaches daily.

I’m three days late now, when should I take a test, and what kind of test is the easiest to interpret?