pills eh? well your dealer man was probably just wanting your cash. let me give you a small lesson on mushroom pills k? usually if you have a double "OO" size gellatin cap they will have a weight of 500 mg on a tripple beam balance. now subtract 100 mg for the actually container and your left with 400 mg of shroom dust. If that is in fact what your refering too. Now each of those pills will contain a half gram of psilocybin. So in actuallality you did not eat a 8th of shroom but a half gram..........which is a very, very, small dose.
best of luck in the future,
PS. go kick who ever sold it to you's ass! :)