Is pills a upper or a downer?

Marijuana is considered to be a downer (along with benzodiazepines, barbiturates and alcohol), since it increases melatonin production ( Melatonin is a hormone produced by the pineal gland and it controls the body's sleep-wake cycle. This simply means that it determines when you sleep and wake. The pineal gland, which is located at the back of the brain, releases melatonin when you are in a dark place. This takes place mostly at night, thereby inducing sleepiness.) and generally depressing your physical functioning (muscle relaxation). One may sometime see it as an upper, but that mostly occur when it is a full sativa or a mostly-sativa hybrid, because of its energizing and up-lifting characteristics, but it is still a downer.

Uppers (Amphetamines, Cocaine) induce alertness and wakefulness among other, which characteristics are almost the complete opposite of the effects of marijuana and other downers.

That is why downers are commonly used after taking uppers, to reduce the anxiety/hangover which often appears after one has stopped taking the upper-substance(s), so the body and mind can recover.

Conclusion/short answer: Marijuana is a downer