It can't hurt to follow up with your GP or Gyno. Spotting can be a symptom of endo but may not be the only cause so you are best speaking to your doctor. The doctor may order an utrasound - I found an internal one was more accurate than an abdominal one. I had had a number of abdominal ones over the years and I was told that there was nothing showing. A year ago I went for another one and was a little naughty - I forgot to drink the water in time and it ended up in me having to have an internal one. - But it was a blessing in disguise as what the external abdominal did not pick up the internal one did and after a year on the public health waiting list and finally having a Laproscopy (SP?) I was diagnosed with very severe endo requireing immediate surgery.

The only way to tell for sure that you have endo is by having a Lap as far as I know.

HTH

Good luck.