When should I test??

[Davis1016]

So I'm not sure when I ovulated. My last period was March 6th. My cycle is usually 28 or 29 days. I have no signs of AF at all! I usually have lots of spotting before I start. I tested yesterday and today and both were bfn. I have watery discharge, backache, headache and sore breasts. 🤷🏻*♀️ I feel like a test should already be showing bfp if I were pregnant by now... but totally stumped!