Seperation Anxiety at 4 years old??

I don't understand this new change that Gwendolyn is going through. She has always been this super outgoing, doesn't need mom, kind of girl. It started on Easter Sunday, she was happy to be going to Church, practically skipped up to the door of the church. The second we enter the doors she put her brakes on and wouldn't move and wouldn't look up, just kept saying she was scared. We were late and the Church was packed, so I didn't handle it well, I just dragged her crying self to a seat and scolded her odd behavior. She then didn't want to see her Grandma who was sitting with us and didn't want to go to the nursery where Owen was. Once we got her to the nursery, she sat by the door for the first half of Church before she would go play and join in. I tried talking with her about it later and all she would say is she was scared. Yesterday I went to drop them off at the daycare lady they go to one day a week. She has been fine going there for many months, once she got used to it. Yesterday, not so much. From the minute she woke up she insisted she didn't want to go the Cheryls, she wanted to go to Grandmas. I tried letting her know that wasn't an option, grandma had work to do. She was quiet on the way to Cheryls and started whining once we were there that she didn't want to stay. I tried letting her know she could call me at work anytime she wanted and that Daddy would be home from snowmachining that night and we would all play a game together. Still crying and clinging bad. Owen is off playing, amazingly enough. I don't know what to make of it and finally just leave her there like that. I call later and Cheryl said she was just fine minutes after I left. It hurt like hell leaving her there like that though. Again this morning with the pre-school drop off. Normally she runs in ahead of me and is gone, I have to hunt her down for a kiss good-bye. Nope, she wanted to be carried, she didn't want to go off and play even though two little girls (Callie and Bethany) each came up and asked her to go play with them. I held her and hugged her, thinking she just needed a minute of that. Never got better or out of her funk. Finally just handed her off to her teacher and left with her crying. This SUCKS and I want it to end. I talked with my cousin for a few minutes after drop-off and was able to peek in and see that she was fine, sitting a little off from the circle, but fine. I just wonder what sort of effect me bailing on her is having on her poor little mental state and motherly bond. I get the anxiety when there is a change and she is just starting a new routine, but we have been doing this same thing for over a year.