Ditto to all of the above. Maybe this will give you some perspective:
I started with portion control when I was somewhere a little over 300, and started logging calories when I was in the 260's because I plateaued and wanted to see what was going on. I was honest with myself, and I was shocked to see that even with watching portions and cutting out fast food I was still eating almost 3000/day. God only knows what I was eating before that--I lied to myself so much.
When I started counting to lose weight, I actually AIMED FOR (get this) 2500 and still lost more than a pound a week, steadily.
Now I'm in the high 230's and eating about 2300, though I aim for 2000. I've only recently started hovering in the same spot on the scale, for the last month or so, though officially I'm down two pounds the last four weeks (but I'm not convinced it's for real)--so I'm going to actually exercise every day

and stick to the 2000 more religiously.
I'm thinking of zig-zagging 1800 some days and 2200 when I don't have quite as much control over my environment.
Bottom line: Some of us are big girls--we gotta eat or our bodies are gonna get really ticked!
BTW--If you've lost 31 lbs already, why are you looking to change your calorie intake drastically? Seems like you were doing okay--is there an emotional component here that might throw you off track even more than the technical diet stuff?