Yes, I would appeal. There have been a lot of problems with ESA and many people found capable for work have appealed and got the decision reversed. Going from 0 to more than 15 points is not uncommon. You should get help from CAB or similar organisation. The "Benefits and Work" website might also help you understand the appeal process - benefitsandwork dot co dot uk - I am not able to post links until I have posted ten times.