Sleep

My son just turned 3 months and I was wondering about his sleep patterns. My son usually sleeps from 9 pm to 12 am then from 12 am to 4 am and from then on out wakes up every hour or twice and hour until 7 am and will not go back to sleep. I'm a FTM so is this normal? A 3 month old only sleeping 3 hours at a time? I keep reading my whattoexpect emails and I see on other sites that at 3 months they should be sleeping in 6 hour stretches at night. If so how do I get him to sleep longer? I feed him more during his night feedings and I bathe him and massage him before sleep but nothing increases his sleep.