Help!

My son who is just shy of three weeks is difficult to put down to sleep especially at night. He will wake to eat 3 oz of formula and then be restless for 1.5-2 hours before eating another 3 oz. of formula. We've been transitioning him to gentlease formula for the past week. He hasn't popped since Friday. I'm tired and starting to lose it... Any idea if this will be a forever issue I will have to deal with?