I don't think it was the bulb, it was brand new and all I did was unplug the old one, plug in the new one. Didn't have anything turned on at the time, etc.
piper, I'll wait till morning and see how it goes. I've only been riding a year, am not mechanically inclined yet and haven't had any trouble till now so I don't have any troubleshooting skills either. Now that you say it, when I was riding I was wondering if this is how it feels if it's only firing on one cylinder. My problem is that I don't know cause and effect yet.

I'll check the plugs, haven't checked them before so they're probably due for a cleaning (wire brush?).
Thanks!