I need some help and words of encouragement.

Hi, About 3 weeks ago I decided to make some lifestyle changes in order to lose weight and get healthy. I read a few posts to help get me started. I started an account on myfitnesspal, I have cut my portions, changed my unhealthy snacks to healthier ones, and do 30mins of treadmill on full incline for 30 minutes four times a week. I've even cut out all sugary drinks and strictly drink water. Despite my best efforts, I haven't even lost a pound and I'm starting to feel discouraged. What am I doing wrong? What should I be doing?