My 18 month old is acting totally different after I left him for New Years.?

On New Years Eve, my fiance and I went out for the night, which we hardly ever do. We left him with a girl that I trusted. He has been good about going to bed at 8p and sleeping through the night. I put him to bed that night and then we left. Shortly after we left he woke up and cried and she couldn't get him back to bed so when we got home she was in the chair asleep with him and that was fine it didn't bother me. But since that night, I can't even get his pj's out and he is crying and not wanting to go to bed. He cried for 45 mins in his bed one night b/c people say just let him cry and he was crying so hard i just had to go get him. Then I put him in our bed and he would wake up throughout the night and cry, but he wasn't hurt or sick. Also, he now crys as soon I pull up to the daycare and he use to like the daycare. I am just lost at what to do.... terrible twos early?...just a phase?... HELP ME!!!