PIP Scored 0 points after phone assessment

I rang the DWP today to ask how to send in a letter from my GP and discovered that my PIP claim had been disallowed because I had scored zero points. I knew I hadn’t done very well after the phone assessment as my brain was really struggling and I had put on my form that someone would be there to help me and then I couldn’t get anyone to do that.
I was advised that I could do a mandatory reconsideration but that I could put in a 2nd claim at the same time. Has anyone done this and is it really necessary? Bearing in mind how stressful the whole thing is. Has anyone got any advice?
Thanks.