Implantation bleeding?

Georgia
Hubby and I have been trying for 3.5 years to get pregnant (I have endometriosis, so we knew it was going to take time). This month I tried something different. I put his sperm into an instead cup, and wore it for 12 hours whilst ovulating. 
5 days later, I have sore boobs, weird stomach cramps and sensations, a nervous stomach (like butterflies, only a little stronger). I just went to the bathroom and when I wiped, there was a little brownish/reddish blood. Sorry if this is TMI. 
My period finished 7 days ago, so I'm not due on. And this doesn't feel like a period feels. I put in a tampon just in case. But could this be implantation bleeding? When can I take a test? I'm 5 DPO