I decided to switch levelling mods from oblivion XP to realistic levelling and upon loading the game my level has decreased by 6 from 13 to 7, I tried using the "advlevel" command to force a level up and the "player.setlevel" command to just set it back to 13 but it just jumps right back to 7, is there a way I can prevent that happening because dropping so many levels I now have stats that's way to high for a level 7 character? :confused:

You require a clean save after disabling XP and before loading Realistic Leveling.
Once this is done RL will recalculate your attributes and levels.

Didn't do a clean save the first time round and done it just now and I'm getting the same result, how can it's recalculation possibly make me descend 6 levels...oh and it's also pushed a few of my attributes up by around 30 points :mellow:

You are going to have to dig into the readme for RL and look at the settings - perhaps RL is set to level slower than what OBXP was.