Wondering!

soo my DH and I have been trying for baby!. I have been patiently waiting the TWW.  AF is suppose to arrive in 3 days. I am on a regular  cycle and my predictions have been fairly on point for the last 4 years. Today AF decided to knock on my door. but what i think is my period does not seem regular. i would say started out medium. now a few hours later is lighter. still enough to change my sanitary napking but only visible in the napkin not the toilet bowl .. sorry for the TMI . i think is my monthly visit because of the color. 

Has anyone  ever experienced this? someone told me about implantation bleeding but it seems a bit more than spotting . i will check my flow in the morning. 

i will note that my symptoms the last week or so could have been PMS just not sure.. 

thanks in advance for the advice!!