Beginners ! Problems with driving lessons

Hello and good day to you! I don’t know if there is something like a beginner group here ? let’s see. I bought a streety in the late autumn which I love very much. In the driving school I drove KTM: Kawasaki : Honda (was just changing time 🙂 then I changed the driving school and now I have a great driving instructor who is driving motorbikes too. Much better! He says I sit and look good and we have already driven a lot on highway. Unfortunately they only have BMWs . Now sit z i am on a GS f750 and don’t understand the world anymore. Because of winter / flu time and now lockdown I used to practice with my streety in a private parking lot. That’s great (not yet perfect ) so slow down slalom / 8th drive/ stop and go/ on the mountain….there it is a bit steep etc. Now I’ve already fallen 3x in 2 days, always stopping. That’s so prostatic… still comes up with something 🙂 in other words : I’m too stupid to stop. Can this be sooo different ? The poor moped doesn’t get better either, is certainly great German valuable work but I somehow don’t get any real contact with her 🙁 I’ve never fallen down with mine yet (is also a little lower but not much)….I asked if I can bring my own to the driving school. Was rejected. SCHNARCH!!! what do I do now complain…. mimimi…… am really unsure. Does anyone have a tip?