My bitch came into season on sunday I think !!!
Since then she has not really lost much blood, on and off
I am wanting to mate her this time but am a bit concerned due to her odd season !
She is very swollen and my male dog is very interested
Can anyone give me any ideas

Bitches don't always produce copious amounts of blood. Some will only produce enough to just make a slight mark on a tissue, some none at all, others will drop blood everywhere they go. They are all different. You may find that she produces a bit more blood as the season gets closer to mating time. Or not. If you are wanting to brred from her then the best thing would be to get blood tests done, that way you won't miss the optimum time.