Caffeine

I couldn't get my regular decaf teabags when I went to the supermarket a few days ago, so I bought 'normal' teabags, which I do drink occasionally anyway (although not more than one or two cups per week). I've just remembered why I gave up caffeine - I've been drinking the normal tea for three days and have had a massive headache for two of those days. Think I'll switch back to the decaf...