Question About Sleep

So my 5 week old sleeps about 45min - 2 hr naps during the day (granted the 2 hr ones he needs assistance to get through each 45 min cycle). At night we have our bedtime routine and he's down at around 8-8:30pm. He has a great stretch until 11:30-12:30 for the most part. He then has a feed and is down at around 1-1:30am. Our problem is after that feed, he is up again within 2 hrs, and then he's up every 45min - 1 hr. Is there any way to get him to do a second 3-4 hr stretch after his 1am feed? I thought around this age they got better at sleeping longer :s