feeling discouraged

Not sure if it has been mentioned, but make sure that you're weighing your food. When I first started on here, I used to measure and sometimes guess my portions. Then I got a kitchen scale and it turned out I was often WAY off. Also, are you using a heart rate monitor for your workout burns? The numbers given on MFP are not always accurate. These are just some things to keep in mind. People tend to tell you on here to "up your calories" all the time...that has never actually worked for me. I wish it did though!

I do have a hrm and I do measure my portions and try to bring food to work as often as I can

Then, in my very unprofessional opinion, it truly sounds like you're not consuming enough calories. Look up a thread on here called "In Place of a Road Map." It talks about all your numbers and how to figure out calorie intake as well as informs you about your macros. I strongly encourage you to read it and ask the guy questions. I am following his advice (plus I did some research on my own, of course), and as I mentioned, I've lost 7 pounds in 5 weeks.