Restricting can make your blood pressure really low, and purging (if you do it) empties your body of potassium which can cause muscle weakness. I experienced this a lot when I was actively doing both, I actually have a scar on my face because one day I fainted dead out and my tooth went right through my lip. All you can do is be very careful when sitting up, standing up, going up stairs, hold onto something if you can.

The only thing that will make it start to get better is being in the recovery stage and having a healthier body. For now, just be careful, you can really hurt yourself if you fall (especially since restricting makes your bones very weak too).