I have ms. lately i've been so weak and i try to walk but it's such an effort & very exhausting. left leg is dragging. will i ever go back to normal?

If treated: You do not list any specific medications, or specific therapeutic interventions, and not clear to me if you are now into a secondary progressive phase. This can be treated and managed, but you need an experienced ms team, which is more often associated with a local medical school. There are multiple ways to improve your function, and if you are experiencing relapses, get treated asap.