In reply to Nevis-the-cat:
> Medical professionals tend to be knowledgeable about medicine, everything else is just woo.
Aye, but the average GP will know bugger all about the medicinal effects of certain herbal concoctions (not homeopathic sugar pills) because they are trained in the use and effects of the manufactured drugs derived from those plants etc. Dried and compressed Meadowsweet doesn't make it into BNF, but lots of salicylates etc are.
Herbal medicines are different to homeopathy in that they do contain active ingredients that do have a noticeable effect on the body, good or ill. However the concentration and levels of that ingredient within different herbal products varies greatly and the packaging is often inaccurate.
Tim Minchin should probably revise his quote to say
"You know what they call alternative medicine that's been proved to work? - Medicine... and lots of other things with proven medicinal efects but are a bit unreliable and should be treated with caution"
To the OP: I would be extremely cautious about continuing with feverfew. If the headaches are muscle-tension related then maybe meditation and regular stretching could help?