Is there a way to search questions that a specific user (me) has upvoted? I looked at the advanced ninja search options, however I didn't see anything, maybe I'm just missing it.
No. It's not even available via the data dump.
However, the system does display them when you visit the question, so in theory you could build a screen scraper that gathers the information for you.
But there's no easy way.
If you think you want to refer to a question you've upvoted, consider marking it as a favorite by clicking the little start below the question voting spot.