First of all,
drop the thoughts. Fear is bad advisor, and if you think that you gonna hurt yourself, you eventually will. Strengthtraining isn't just physical science, the biggest part plays in your head.
Second, start doing some serious HIIT training. Especially running and swimming, it balances out your body, and it can also benefit your mma-training.
The biggest mistake BB make, is that they don't use their body as a whole instrument, they always focus on or two bodyparts a day. Including a hiit makes sures that you will use every fibre in your body.