Yes, it's normal. Since your channel is still small, you're not going to get a lot of interaction. Majority of people don't leave a rating, and even less seem to comment. On my vlog channel I have almost 800 subscribers, but only 30-35 of them actually interact with my channel.
Your sub growth is normal too. Growth in the beginning is very slow, usually first 100 subs are the hardest to achieve. Then after that, you begin to slowly begin to see a steady growth. So it's normal to go a week without gaining a sub with a channel your size. YouTube is like the snowball effect. When you're small, you will slowly grow. When you begin to get a bit bigger, the faster you will grow.