What Causes Pinkish And Light Vaginal Bleeding After Having Sex?

2 Days before ovulation my boyfriend ejaculated in me on the 14th and the 15th iwas having cramping pains and sore swollen breast tiredness and nauseous for the past couple of weeks on the 5th i came on my period with light pinkish spotting and on and off cramping the following day my flow was light with bright red bleeding with the same on and off cramping and in 4 days i came off my period could this indicate implantation bleeding or was that my regular period?