Make sure you are on the right account on your system. If you are, and they're still not there, do this.
1. Turn off the system, if it isn't off already.
2. Unplug the system from both the wall and itself.
3. Wait 2 minutes. If you do not wait a full 2 minutes, it may not reset properly.
4. When you are done waiting the full 2 minutes, plug the system back in.
5. Turn the system on and check to see if the games are there.
if this does not fix the issue, the system may have had an issue with memory loss, so it is not certain you can get your games back. Check the eShop to see if you can redownload them, but if not, you will need to contact Nintendo to see if anything can be done about your games.