For the past few months on and off my dog has been sick, and had the runs, can't understand why as not changed his food or anything else.  My other dog a SBT bitch puppy who is 8 mths old is fine and never sick. 

He has recently started to sit down and although it looks like scooting, he is not,hes  just sat there kind of rubbing his behind whilst he is sat down. I do worm them both and I am aware it may be anal glands that need to be emptied.  Would you think this has anything to do with him being sick?
I will take him to the vets just wondered if anyone had experienced this, many thanks

Your dog does sound like it is in some sort of discomfort which as you said could be his anal glands, maybe the food he's on doesn't agree with him or is he one of those dogs what eats all kinds of the floor.  I believe it would be definitely worth taking him the vet and getting him checked over and while your there they'll empty his anal glands and if there not full you'll know it's something else.  Good luck with your boy.

Warm regards Susan