Breaking Through
I too started last spring, could not do 50 yds without gasping for air. I went through two swim classes and finally found a person that specialized in tri-training/swimming. Working in a lake with a swim instuctor really helped me get where I needed to be.
I don't like counting laps but I now swim 3x a week, I swim non-stop for 30 mins no rest. Then 30 mins of hard intensity speed work with frequent stops. I can't wait to spring to start swimming in lakes. Open water swimming really pushes your abilities.
My advise is the same to struggling swimmers, the first 3 months suck then things will really start to click.
P