Hi,
I had intercourse during my fertility period(towards the end of it) on 26th May. The condom broke. I took Plan B within 24 hours. Now ( 8 days after intercourse) I am experiencing odorless light reddish bleeding like the start of a period but without any other regular symptoms of my period except for slight bloating.The bleeding has increased slightly over the past few hours just like my normal period. My last period was on 12 May and I have a 25-26 days cycle. So my next period is due on 5/6 June. I have taken Plan B before and not experienced early period. Could this be implantation bleeding or just an early period due to Plan B? Am I pregnant?

Lighter bleeding or a change in your cycle is sometimes a side effect of Plan B. It doesn't happen to everyone, but it is on their list of side effects. You may want to try a HPT, although it may be too early for them to detect anything.