Swimming! Hopefully it's getting worse before it gets better?

I had my first master's class last night!  It was really really fun, and the coach gave me so much feedback.  I'd been able to swim about 1000 yds without stopping, just kind of toodling through the water and not getting too tired (about 2:30/100yds). 

Apparently I had the least efficient pull ever, so the coach gave me lots of things to work on to become more efficient. 

I felt like a wildebeast or something splashing around in the water, trying to get the technique down!  And I can't swim nearly as far before getting tired.  And my arms are super sore this morning (in a good, I-worked-out-yesterday kind of way).

I'm hoping that once I get it all down, things will start working together to help me get faster and more efficient.  It's mildly frustrating, but also fun at the same time.