Signs of low supply

mb314

Breastfeeding has been going well, and my son has been gaining the weight he should.  I was cleared yesterday for exercise at my 6 week appointment, but have been warned by my midwife and others not to overdo it because it could affect my supply.  I'm not sure how to tell if my supply is being affected by too much exercise (this is all theoretical right now - I barely ran 2 miles at a 13 minute a mile pace today). 

 What should I be looking for to know if my supply is low?   I know I should make sure there are an adequate number of wet diapers.  I don't know how to tell if he's gaining enough weight now that our pedi appointments are further apart.