Daycare drop off nightmare

DS just turned 2 and we just got back from an 8 day vacation,, so he was with DH and I 10 days total and we had the best time. Since we got back on Friday, he has been a disaster. He is giving us problems going to bed at night, screaming crying, waking up in the middle of the night (sometimes we dont go in, sometimes we have to).  He is also a nightmare this week at daycare drop off. DH said this morning was the worst he has ever seen him. On Monday daycare told me he had an emotional day and was mopey. This morning I called to check in about a half hour after drop off, and they said he calmed down and ate 2 breakfasts haha. I am sure its just about getting back into the swing of things,but I am wondering if this is more normal natural 2 year old behavior. I have read that around 2 children start to get night terrors, afraid of the dark, separation anxiety peaks, etc. I guess I was spoiled because bedtime was always easy for us and hes been great with daycare for a long time. Anyone else going through something similar with a change in behavior?