Hi Lola, no it doesn't make you mental - well it's never done with me (I don't think!).
Some people get bad headaches, feel tired or run down - others, me included, don't have any side effects at all - though now I've tempted fate saying that I'll probably get a killer headache tomorrow.
Don't worry about doing the diet, if you do have any bad side effects they will only last for a couple of days and you can take painkillers.
Good luck with it....