Strings are the #1 most important biggest factor to the feel and sound of your bass... obviously making a drastic switch in strings is going to make a big difference! It's like switching from briefs to boxers, things are going to feel a little "loose" at first.
The obvious question is, have you properly set up your bass since changing strings? Intonation, truss rod, nut, saddle height, pickup height? If you're not comfortable doing these things yourself, take your bass to a pro for a setup.
I am a big fan of lighter-gauge strings. I enjoy having to play with a lighter touch, and yes, with practice and a good setup, you should be able to play pretty well with your 220's.
But if you try and and don't like it, go back to the 165's! It's of utmost importance that you play the strings you like, good luck!
