I started bleeding on day 13 - i do not know if I ovulated before this day - I am usually 26 days cycle. I am very regular. Concieved my first son 4 years ago on Repronex. Did not have implantation bleeding with him. What does implantation bleeding look like, could it be early menopause, could I be miscarring - can you tell I am freeking out?
Please let me know what you think

It's too early to be be implantation bleeding. Is it possible you conceived last cycle and are pregnant right now, experiencing some first trimester bleeding? Did you have a pregnancy last cycle?

I did have a regular period less than 2 weeks ago that was no different from any other I have had and right on schedule. I guess I could have become pregnant last month as we have not used any means of preventing pregnancy these last 3 years, but I was not on any fertility drugs.
It looks more and more like a regular period with moderate to heavy bleeding. Why would I suddenly have a regular period at 13 days into my cycle? This have never happened before. I have considered waiting another year before going to the RE, but know I think I shouls go as soon as possible to figure out what is going on

In addition to implantation spotting, there is such a thing as ovulation spotting.

But if it's more like a period, it's just possible that something put your cycle out of whack.