What's the appropriate way to breastfeed and help baby gain weight? Dr's have me pumping only and no breastfeeding. I feel like my milk is reducing.

Breastfeeding. Usually, feeding on demamd, straight from mom, is the best, most efficent way to breast feed. Why are you only pumping? There can be good reasons to go that way, but it may make it hard to keep supply up. Having a picture of baby to look at while pumping can help. Read "so that's what they're for: breastfeeding basics" by janet todaro for other pointers.
Hard to say. Hard to say from this exactly what's going on with the baby, but only pumping and not breast feeding can sometimes cause a decrease in milk production. Check to see if you can do some direct breast feeding to improve your supply, and make sure you are double pumping with a hospital-grade pump at least 7 times every 24 hrs. Hopefully you will be able to transition to breastfeeding soon!