Re: feeding from one breast
One side is just fine. Or you can let baby completely finish on the first side and then offer the second breast. Then on your next feeding offer the last one first. Limiting each feeding to one breast may help with gassiness and if you feel like your supply is fine, try it for a few days. Should not be a problem.
Also, the amount you are pumping is a lot. Which is fine to do but it may be causing over supply. So in your case I think feeding on one breast may be a good idea.
Hope that helps!
To free us from the expectations of others, to give us back to ourselves - there lies the great, singular power of self-respect. ~Joan Didion