You are probably fortifying your Restoration Skill. Skill perks (eg the type of spell you can cast) is based on the "natural" unfortified skill level. If you look and your Restoration Skill number and it is Green then it is fortified.
This, if you've got an enchanted item you're wearing, your restoration skill is increased but you can only cast to the power of your natural skill. Took me a while myself to understand why i couldnt cast spells that were below my (green) skill level. Just level it up however times neccessary, in whatever way your personal RP rules (if any) allow you to. If you have no rules for yourself just wander around healing yourself until your at the level you wish to be. :foodndrink: