Hi @GiedreM,
I was actually encountering simlar issues. I tried to use different Rasa versions on different Anaconda venv, however, they kind of seemed to mix and I broke everything… 
I asked about that in the forum here and got the following solution:
instead of conda create -n nameofvenv python==x.x.x, you should use
conda create -n nameofvenv python==x.x.x anaconda.
Maybe that solves your issues?
Ciao, Vio 