Worry: The Saga Continues

I had my 24 week OB appointment on Friday. I was feeling pretty relaxed about the whole thing: we weren't going to be having an ultrasound and it was with a doctor that I had met before and liked (there are several doctors in the practice I go to), so I wasn't worried about either of those things. I knew we were going to get to listen to the heartbeat again, but I didn't have any worries there because I've been feeling him moving so I was confident we would hear it just fine.

But it's always something you don't anticipate.

She put the wand to my stomach and there was the heartbeat, nice and fast. And then it slowed down. Way down. I thought maybe she was picking up my heartbeat instead. She moved the wand slightly and after a few more seconds the heartbeat sped up again. And then it slowed down again, and stayed slow for probably 10 seconds or so. Then it sped back up. I started to get a little freaked out. I asked if this was something we needed to worry about. She said that no, as long as it sped back up, it was nothing to worry about. She said it was probably the baby just grasping and squeezing his umbilical cord. Not a big deal.

At the time I accepted that this was nothing to worry about. An hour later, upon reflection, I started freaking out. I went home and laid down on the couch and put on some music. Usually he would be very active in that situation, but he was quiet. For about an hour and a half he was quiet, and then I felt some soft movements. After I ate that night he moved around a little bit, but he was quiet through the night and into the next morning, even after breakfast and apple juice. That's when I called the after hours line (this was Saturday morning). I was instructed to drink a tall glass of cold water and lay on my left side for an hour and see what happened. This did in fact perk him up, and when the nurse called back I was more calm. But for the rest of this weekend he's just seemed quieter than usual. Also, at our 20 week anatomy scan, the umbilical cord was around his neck. The u/s technician seemed unconcerned at the time, and I tried not to worry about it because I continued to feel him moving, but now I can't help but wonder if the heart rate decelerations have something to do with that.

I can't figure out if I'm worrying unnecessarily or not. My worry compass is officially all screwed up. I would like to call tomorrow morning and ask if I can come in and hear the heart rate again, and if it's still slowing down, get an ultrasound, but is that crazy?

I googled the heck out of this, trying to find someone who had the same experience and was (hopefully) reassured by her doctor, but came up empty. Has this happened to anyone?

Should I be worried?