How about walking to work? Taking 3 times longer than biking sounds like a drag. I wonder how long it would take you to walk there?
I find that if bike riding is a "chore" then I won't want to do it. I do it because it's fun. Maybe if you could search out (not sure about Seattle, so I can't recommend any place specific) some fun or interesting places to ride it would be a nice change to the "same old, same old" of going back and forth to work.
Don't give up, just make it fun. If you're new to the area maybe ask around. I think there are some flat places by the lake.