I don't know if it's the "wrong" gear, mental, nutritional or I'm just out of shape. I'll be powering up the one hill (not very steep, about .4 mi) at a good pace (14-16mph), in a relatively low gear (middle chainring, larger cogs), and then....bam, I drop to like 9mph, and it's all I can do to make it up the remainder of the hill to the stop sign.

Thoughts? Suggestions?