I just started up The Witcher 3 after a couple of months and plan to do the Blood and Wine expansion, but it when I look at my exp/level bar, I'm on 60,000/2,000 exp, and when I get any exp, I instantly get 30 levels..... I don't really want t play at lvl 68, it won't be fun if it's easy. It's the same on old saves too... Has anyone else experienced this?

I've not used any mods.

If I go back far enough I don't have the extra xp, but I also saw that my vitality is the same at lvl 38 to 68, is the only difference 30 extra skill points? If so I can live with it, not like extra skill points gives any bonus at that stage.

Try the CDProjectRed forums. I don't know of any solution to the issue you are having.

Maybe try playing through and seeing if it corrects itself. As always - ensure you have all the latest updates - patch, DLC package and expansions installed properly.

You could try a re-installation by downloading all the latest components and reinstalling (keeping your save games), though I don't know if it will solve anything. Worth a try...

I made a help ticket for that a few days ago.
Unfortunatly this can not be fixed.
You can try to reroll patch, load and save game and then repatch.
It only effects pre blood and wine saves.
Good luck!