That's normal. The third is Xmas this is normally only available over the Xmas period, but this year it was withheld due to technical problems. You are not really missing anything it is very repetitive due to not many sentences being available.

Congrats on your great streak :)

Have you tried out the Stories in the "Labs" section? They're a lot of fun.
Also, if you have a mobile device (IOS, Android), try installing the Duolingo app and check out the bots feature. Also fun!