Spotting and cramps 1 week after ovulation

Katy
Hello,
I'm experiencing some very strong period like symptoms today- spotting (which is quite a moderate amount) as well as cramps both in my ovaries and back. 
I've been TTC and was ovulating last week. I'm currently in the week between ovulation and my period, so I'm not sure what's going on, and I'm a bit scared about what could be happening. 
This has happened to me before, about 3 months ago (been TTC for 6 months now), and when I told my doctor about it she said this is sounded like a chemical pregnancy (basically an extremely early "miscarriage" of sorts). 
I'm just wondering if anyone has experienced this and can give me any insight into what it may be? I know implantation can occur anywhere from 6-12 days after ovulation, but this seems a bit excessive to be that and also wither all of the cramps, I'm just not sure.
Any advice would be appreciated!