flutters, kicks and a disapearing belly button

I felt the first kick on 11/11. It felt like someone thumping a melon, or in this case, my uterus. They are few and far between, but I know that's going to change. I was at the store yesterday and felt 3 strong kicks against my hand, so he's getting bigger. My stomach is tender to the touch and my belly button is getting shallow. Sleeping has been a bit of a challenge. I'm most comfortable on my left side, but not for 8 hours. I know this is only the half way point and I'm going to wish for the way I feel right now in 10 more weeks, but it's all relative. I have an appointment with the birth center on Monday. The last time I saw my midwife, she said my fundal height was high..."could it be twins?" I told her, "NO WAY! there's only 1 baby in there". She followed up with, "ultrasounds miss twins all the time." We had an ultrasound scheduled for a few days later, there's definitely only 1 baby in there. I heard that you can hear the baby's heart beat with a stethoscope around 20 weeks. I'm going to try to find a quality one before family visits next week. I think it will be fun.