I don't do MFP anymore, I use old fashioned pen and paper.
I used MFP forever and then realized it's more efficient for me to write it down physically. Sounds like I'm 100 years old LOL.
If you are truly eating 1600 (not doubting you!), then you have a deficit of 600 calories more/less a day based on your current weight. Add in your exercise and you should definitely be down 1-2lbs a week. I do agree with the above posters though that you could be losing inches. Do your clothes feel better? Are you working out very intense and maybe retaining some water in sore muscles?
We will get to the bottom of this for you. Just don't give up no matter what.
And sorry for all the questions, it sounds like an interrogation and I promise it's sincere help and concern!