Greetings!
The good news is that you are progressing nicely. The other good news is that you are right on track and everything is typical and normal. More good new: 1 1/2 weeks is nothing other than maybe a minor lesson in patience. I have bounced around the same 3-4 lb range for more than a month. Progress slows to an almost imperceptably slow pace sometimes but it comes.
1. Make sure to drink lots of water
2. Stay away from any frankenfoods
3. Make sure you get enough fats
4. Count your carbs. Use Fitday.com for awhile...it helps with accuracy and to avoid carb creep.
5. Find the right level of calories. Not too high. Not to low. It's about experimentation here as it's a little different for everybody. Figuring this out alone can take several weeks of playing around.
6. REMEMBER: Losing is great but not gaining is in itself an achievement. Focus on the positive.
IMHO.