3200 is a fairly high maintenance level. If you're large framed, muscular and active that can be a reasonable level; however, if you're more normally composed you will want to adapt to a lifestyle where a lower calorie intake maintains your weight. If you don't prepare yourself for smaller portions more often and eating nearly only natural and healthy food, you can expect to gain back weight. I'm sure 2000 calories right now feels like you're limiting yourself significantly, but after you get to where you want to be, you aren't going to be able to start eating lots more and still maintain your new lower weight. Your overall lifestyle will dictate your health and weight and weighing 200 pounds involves a totally different lifestyle for someone 6'2" than the one for weighing 250 pounds.

You mention that you were previously exercised not at all. Part of why your weight loss has slowed is probably due in part to your gaining muscle. As you ride harder and longer, your legs are going to build up muscle you may not have had before. Ultimately this is good and will help you burn more calories, but it might look bad on the scale in the short term. What you need to do is look at your health overall. You probably notice going up stairs is noticeably easier; your body fat percentage is probably noticeably lower. Realize that whatever the scale shows, you are certainly much healthier now than you were a month ago.

The key to it all is having a broad, long term view. Being thinner isn't the result of a diet, it's the result of living a different sort of life. To get there you need patience and to stay there you need discipline. If you stick to it, it will work, though it may take a little time.