Sounds like it could be a good sign of implantation bleeding. Hopefully, your blood work is due soon so you can find out for sure. Good luck and I hope this is the one!
I agree with Emilia105. You could be having implantation bleeding/spotting. And the sensation/cramping could be the result of your uterus expanding due to a successful implant. How many days do you have left until your blood work?
when was your IVF? spotting/discharge is normal after IVF, as it could indicate implantation bleeding, where the egg is attaching to your uterus lining. cramping is also normal after IVF.
did you have your blood work done your after IVF? is your beta and progesterone increasing?