Implantation Bleeding

Question on Implantation bleeding:

How do I know the difference between implantation bleeding, period or anything else?! I have been researching implantation bleeding and thinking maybe that's what I'm experiencing but I'm very nervous and not sure. After a miscarriage and D&C in October I have finally been released to try again. So since I've been in my fertile/ovulation window May 21-26 we started trying a couple of those days.  The night of the 26th I had very minimal dark rusty brown spotting. The 27th and today I had Medium spotting that's been chaninging from dark brown to light red color with small blood clots. What is this?! Is it normal?!