implantation?

So my husband and I have been trying to conceive for over a year with no luck. I recently stopped taking clomid after 3 months with no success and still ovulated on CD 14. On 8 DPO my husband and I BD and after there was a small amount of red blood and only lasted a few moments. This has never happened to me before and the sex was not rough at all. The only thing I can think of is implantion, could it be something else? AF Is due for another week at the least.