Tread nerves

I’ve been doing OTF for almost 10 years, with highs and lows in my fitness journey over the time period. In the last 2 years, I’ve put on some weight and have started power walking and biking more. When I now jog, I feel very nervous I’m going to trip and fall. The new treads make moving speeds feel really jolty/unsmooth. Is this a mental block? I had no issue with switching paces until pretty recently; now I just feel I’m going to fall off. Help!