Breastfeeding and ovulation

Hi,

I'm exclusively breastfeeding my 5 mth old and only had 1 period when my son was 6/7 weeks old. I did an ovulation test 2 weeks ago and it wasn't positive but there was a definite line there which suggests I did/was about to ovulate. Ive been expecting a period but there's nothing as yet. Did an ovulation test yesterday and again a definite line but not strong enough to be a positive. I've taken 2 pregnancy tests and they have come back negative.

My question is, has anyone else had positive ovulation tests and no period whilst breastfeeding? Or can anyone shed any light as to what is going on?

Thanks,

Emma