Client started to lag weirdly lately

Hello Forum, I would need some help about my client and it's weird lags lately. I mean like the last month, the client has started rollbacking my character randomly, returning me to a place 3 to 4 times after i keep walking forward, weird lag and delay after I'm using abilities mostly in pvp. My fps is fine also my internet connection haven't changed to worse. I'm playing in Icecrown's realm and I also tried the Onyxia's 60 realm in which I downloaded a bit addons, some of them were for vanilla and they barely fit the 3.3.5 client and I guess it has something to do with it. I deleted em all except my old ones that I had for WotLK, deleted the cache folder in WoW directory (I got the idea from internet) but the lag seems to stay. Maybe I should try reinstalling the game? Please let me know if u have idea how to fix this annoying weird lags, thanks in advance!