There’s a few things to take into consideration and that is, do you think what they have said in their report is correct in the way your daily disabled life effects you or do you feel they have got it wrong by saying your capable of doing something that your not and here were talking mostly about your capability to walk a reasonable distance in a reasonable time.
If its the first one its best to accept their decision and save yourself a lot of stress but if its the latter go for Mandatory Reconsideration telling them the errors of their way and at the same time ask for a copy of the assessors report because it normally here you will see the mistakes they have made.
If your going for it MR is the first step and you can do nothing more until you take that step, by the way, you may have seen the other thread around here somewhere called “PIP has anyone been turned down” and the advice in there is to get help if you’ve haven’t already gone down that road.
Best of luck and I wish you well.