Very good job, and excellent call on dropping down the gears when going into the wind.
Glad to see you were able to do it today, and no shame in taking breaks. It's only the second run

For commuting, I find it much more relaxing if you just go at your own pace and not try to stay at a certain speed. Go at whatever you feel comfortable at. Certainly not something you should be fighting against when you got a gradual hill coming up. Maybe you can go for speed later when your legs are stronger but it is more important to just keep pedaling now to build up the strength to be able to do it later.