itstartswithken

1200's gonna be tough. At your given weight, I echo what some have been saying in the thread, up your intake to around 1500. When you're playing with the critical minimum of what your body needs, it's really easy for the body to go to starvation mode. Since you didn't mention any exercise in your post, I'd also recommend…

Try changing up your routine. 3 weeks is just about the time it takes for the body to become efficient in a routine, and in your case, that's your walking. Try either bumping it to 2.5 miles or power walk those 2 miles for the 4th week. Anything really to break out of that routine to throw your body off the plateau phase.