Baby sleep advice

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My baby is 10, soon 11 months old and for almost four weeks now we have had problems with sleeping. He will wake up like every hour or so and wants to nurse and then he wakes up all the time crying and is tossing and turning in his sleep. I don't know what to do, I'm so sleep deprived. I thought it was just a phase but it's been so long! He was born almost three weeks early and he's been breastfeeding from the start. He has always woken up every two hours to eat and that's fine, but he has never had trouble sleeping like he has now. I'm not sure if this is normal or if I should worry? He is fine during the day, he plays and is alert. He takes two naps during the day, usually for an hour each. Ever since the sleeping problems started he hasn't wanted to eat much "normal " food, but he's always been sceptical towards it. He's reaching his milestones fine, but his weight has always been on the lower side. Is there anything I can try to make him sleep better? Is this normal or should I talk to our pediatrician about it?