I am feeding, can my baby starve if I have low milk supply? Please help.?

How many diapers is he wetting in a 24 hr period? If it is 6 or more he is certainly not starving. The crying can be normal. I remember my daughter doing that as a newborn and I never had supply issues. Also, don't focus so much on the length of his feeds. Many babies can get all they need in just a short time. As long as he continues to wet diapers he is getting plenty of milk. It sounds like you are doing a great job.