YES!! This is a very common occurance. Think about it...you just dropped nearly 20 pounds in a matter of weeks. This is quite a shock to your body and it's putting on the breaks until it can be reassured that everything is okay. That can take a few weeks, but if you're patient and keep giving your body the protein, fats and calories that it needs to know that a famine hasn't struck, you will be rewarded with more pounds gone. WE may want that fat gone, but our body doesn't know that. It's thinking "Whoa! Why are my fat stores being used up so quickly??"
While we all love the quick losses, it's neither realistic or healthy to expect or try to force it to continue at that pace. As hard and frustrating it is be patient, slower is better.
Average weight loss during induction is about 10% of what you need to lose and then about 5% of what you still need to lose each month after that. I'd say you're doing great with already losing 20% of your goal.