There is some excellent advice if you look around this forum. Many of us here catastrophise.
If this is having a persistent negative effect on your well being I would tell my GP the booklet isn't helping and ask for a Counseling / Therapy referral.
In the meantime a good starting point is the great self help resources out there. Feeling Good by David Burns is probably the best CBT book. Another member here recommends books and youtube videos by Clare Weekes for anxiety. You can also try this Aussie NHS link for a free workbook. http://www.cci.health.wa.gov.au/resources/consumers.cfm
, scroll down for the module on worry.
If you are able to put the effort in some of the above will likely help.
Take care, let us know how it goes.