I need your help!!!

Lucas USED to sleep great at night! I would usually put him down around 8:30pm, he would wake up sometime between 1:30am and 4am to eat, then he would go right back to sleep and wouldn't wake up until about 7am! It was wonderful. The middle of the night feeding would only last 15 minutes total before he was back to sleep and I was back in bed. Life was grand! Well...the past three nights have been bad with last night being terrible! I put the little man to sleep around 9:45pm (late because of Daylight savings and talking to the family on the webcam). I did what I usually do, rock for just minute until he gets dosy, and lay him his crib and he falls asleep on his own. Well about two and half hours later, he was up again. I went in to feed him because he didn't eat as much for dinner and I thought he must be hungry. I only feed him one side during the night because I am wanting to cut out that feeding anyway and I don't want him relying on the nighttime feeding for his calories. Anyway, I fed him and went back to bed. 20 minutes later, he was crying again. I let him cry for a minute, then thought that maybe he was still hungry. Fed him on the other side and it was back to bed, finally. About 2 hours later, he was up again. I let him cry again, and he would not stop. I went in his room and put my hand on his chest to soothe him etc. Didn't want to pick him up, but he would not stop. I picked him up and immediately he went back to sleep. I rocked him for a minute and put him back in bed. Not even 2 hours later, he was up again! I let him cry for over 20 minutes! Nothing. Did the same thing when I got to his room and he went back to sleep. 45 minutes later, crying again! I finally just turned my monitor off and shut my door and he was off and on crying for about the next hour until I finally just went in there and got him up and fed him for the morning. Is this normal? How can I get him back on his sleeping schedule? I need some help because I do not want another night like last night. He had also slept terrible during the day yesterday too with no real good long naps so I thougth that he would have slept great last night because he was so tired but that was not the case. He did have good naps on Friday and Saturday and still slept crappy those nights too so I don't know what is going on and now I have a headache! Momma needs her sleep! What is going on? Any advice? I did only feed him once during the night and when he was awake the other times he was not hungry but I don't know why he keeps on waking up and won't go back to sleep. Help!