This basic question was asked here before.
I must express pleasure in the fact that you asked if you were fooling yourself (rather your body was doing the fooling of the mind, or as others would more kindly put it, experiencing the placebo effect). That is a very healthy and skeptical attitude to have.
Here is the previous answer reproduced for your convenience (as answered by Fabian):
Acupuncture is based on the belief that diseases are caused by blockages of your qi, which flows in so-called meridians in your body. By sticking needles into those meridians you can manipulate the flow of qi and eliminate the blockages.
The concepts of qi and meridians are unscientific, they date back to a time where there was no scientific method and knowledge of human anatomy was practically nonexistent. There is no evidence that qi and meridians exist at all.
Sticking needles into your body still could have some effect, although it will have nothing to do with your qi. There are tons of clinical studies about acupuncture, but few conclusive results. A major problem is that controlling for the placebo effect is complicated, as people usually notice whether you stick needles into them or not. Some of the newer and better clinical trials used fake acupuncture needles that do not penetrate the skin. Another often used method is to stick the needles outside of the "proper" acupuncture points as a control.
Acupuncture is believed to be helpful in a large variety of conditions, I'll take pain relief as an example as it is somewhat plausible that sticking needles into your skin could have an effect on the perception of pain.
A review from 2009 in BJ concludes:
A small analgesic effect of
acupuncture was found, which seems to
lack clinical relevance and cannot be
clearly distinguished from bias.
Whether needling at acupuncture
points, or at any site, reduces pain
independently of the psychological
impact of the treatment ritual is
My conclusion is that acupuncture is just a particularly effective placebo.