My baby is growing up

Madelyn left me last night :( She up and decided she wanted to go to her Nana's. Not a cry, not a hug--without being forced, NO hesitation. 
We had a weekend away at Jessica's, Jeremy's sister.  On our way home, she decided she wanted to see her Brian, my brother.  So, we gave him and my parents a call and met them for dinner.  After dinner, she wanted to ride with Brian, so I let him ride with her and I rode with my parents. We all went back to our house and while there, my mom asked if she wanted to go home with her.  She had no problem saying yes.  After a little while, my parents got ready to go.  So what does Madelyn do?  Asks for her shoes and her baby.  We were all surprised.  No one thought she'd actually willingly go.  So, I packed her up, loaded her in the car, and she waved bye to me.
I called my mom later that night to ask a question, and she said Madelyn was completely fine and was playing with the dogs.  This morning, she woke up, cried for me about a minute, and went BACK to sleep.  When she woke up for good, she was perfectly content eating her cereal and watching tv with her Nana.  She didn't even ask where I was.
This is a bittersweet day.  It was actually nice getting some time for Jeremy and myself and I'm so proud of her for being a "big" girl.  It was also nice sleeping in a little late, although my internal alarm clock had me up not too long after Madelyn's normal time to wake up. It is SO quite around here.  BUT,  I don't know if I'm ready for her to WANT to leave me. It got sorta hard to breath and I may have had a small anxeity attack.  (Not from worrying about her.  I know she's fine when she's with family. ) 
Oddly, I feel that having this time to myself makes me a bad mom. I know this isn't true, and in fact, I'll be the first to say I'm a GREAT mom.  It's probably the one thing I KNOW I'm good at. I guess the problem is, after almost two years of being with someone day in and day out (with the occasional night away), I'm beginning to gradually reconstruct my social life.  Just this week, I will be out of the house both Thursday and Friday night.  Jeremy will have Madelyn, so again, I know she's safe.  Then a few weeks from now, we have a charity event for Jeremy's job we've been asked to attend.  Here again, she will be away for the night. Then, we'll be in New Orleans celebrating some friends of ours last few days of "freedom." (They'll be getting married in May.)  Madelyn will spend the weekend with her Grammie and Papaw.  I feel so selfish taking some time to myself though, even if some of the events are obligations. There's no way to rationalize it. Jeremy has told me over and over and over that I'm pretty much crazy.  I know it's okay to do stuff and I definately know I need it, but it just feels so... wierd and selfish.