spoiled newborn?

My son just made 3 weeks, this Tuesday 10/11. Prior to this he was getting much better at latching (he's exclusively breastfed), eating longer and sleeping great. The Monday before he made 3 weeks we had a rough night, he was very fussy. I would try and feed him, but he would only eat for a few minutes before fussing again. Trying to calm him, I continued to switch sides, believing he was hungry. I made sure he was dry and tried to burp him. If while feeding he begin to go to sleep he would wake up once again crying. This went on from about 12am-5am. This happened again last night. I'm worried because I've need hearing I'm spoiling him and that's what's wrong because he didn't want me to put him down. Then again I'm more concerned that this maybe colic. Last night I became very down because he just didn't want to go to sleep and the moment he did and I attempted to put him down he woke up crying again. I just don't know what to do. I nurse on demand because I want to keep my supply up but in doing this I hold him all the time. What should I do?