HELP...i need some help....i am scared..?

i feel like i am slowly dyeing or somthing..i had a hysterectomy a year and a half ago..after that..i started changing.. ( they left one ovary) i felt tired and depressed...didnt want to do or go anywhere..weird...gained weight...cause i stayed home on the stupid computer for a year..no exercise...now if i try to walk or even go shopping i feel pain every where..probably cause i am so out of shape...so how do i get back into shape physically??? I really hurt alot muscular ... i washed my car and almost died 2 days later form my strained muscles....i hate this...help please..what can i do"??? oh and i feel more normal and back to myself as far as emotionaly now....it just physically im so out ot shape....