Your issue is not getting bumped. You issue is you have ideas that just aren't true. Then, you add your concern about practicing combat arts.

If you continue your BJJ, this will be your life. Every hard toss or jerk will have you in anxiety mode. Then, touches like in bed will set you off.

The concept of getting a concussion after a prior concussion has to due with serious concussions. If the 1st concussion caused serious headaches and other symptoms, that can signal that the brain is struggling to maintain proper fluid pressure. A second substantial concussion that happens before the brain has recovered control of fluid pressure can cause a life threatening increase in fluid pressure.

These 1st concussions have serious symptoms and maybe even a brief hospital stay to monitor fluid pressure symptoms. Many years ago, an Olympic snowboarder named Kevin Pearce suffered a serious concussion and returned to training and competition before his brain was ready. A subsequent concussion put him into a coma and almost killed him.