Implantation pain ?

My fiancé and I are trying for baby #2. We started at the beginning of this month. On April 17 I had the worst cramping ever. It lasted probably 30 min and felt almost like a contraction. I started testing last Saturday (6 days sooner test) they all came back negative. I took two blue dye yesterday that had very faint positives. But took a pink/red dye one today that’s a clear negative.

Could I be pregnant? What was that pain on the 17th ? I’ve had a few people tell me that was implantation pain…

All of the ✔️ are days we had sex. Expect for the 17th. The 17th is when I had the cramping. I’m supposed to get my period tomorrow.