Dazed and Confused

Turns out baby boy #2 really enjoys sleeping during the day and waking up incessantly at night. Go figure. The pediatrician tells me to try to keep him up as much as possible during the day. He's a lumpy little meatball who won't open his eyes. How am I supposed to keep him awake. I try to wake him up - he just wants to eat. So I feed him. Then what happens? He falls back to sleep. I know I should be grateful he's sleeping. At least I can get some things done, like post on here, but I really would like him to sleep longer stretches at night. I know he'll eventually turn around and it will get better. I just don't know how long things can go on this way. If babies are supposed to be sleeping 16-20 hours per day, baby boy #2 is up for those 4+ hours at night. He's constantly grunting or crying over night. Right now - you could hear a pin drop he's so quiet. Not a grunt or a groan to be found., but it is only 5:30pm. He's in deep sleep right now and it would be horrible to wake him up. Right? I even tried the bath before bedtime trick last night. I gave him a bath around 7:30pm with the hopes that he'd be stimulated for a while and then he'd be knocked out. He HATED the bath, ate, and fell asleep. I put him down, and he woke up. I rocked him and fed him some more, put him down, and he woke up. This went on for about 1 1/2 hours and then he finally gave in at about 10pm. I thought he, and I, would be down for a nice long stretch. He was up at about midnight. This went on all night. Up, down. Up, down. It's really getting quite tedious. He's eating plenty (I did make reference to a meatball earlier) so it's not that he should be starving and that's why he's waking up. I'm hoping something will change in the next week or two as he gets older/bigger. Either he'll start sleeping longer at night or I'll be much crankier than I am now.