Yep. it's probably your baby you're feeling. Nice eh? This is my third baby, but the first time with an anterior placenta, and it was definitely a little later before I felt regular, strong movements, compared with the others. I think I started feeling definite kicks around 18-19 weeks, or so, after feeling little flutters for a few weeks, off and on, before that. (a mum who's had previous pregnancies will likely feel the baby earlier, so don't worry at all about not feeling much until now!) And don't stress about how much you feel baby moving at first. He will have busy days and quiet days. It's not until a fair bit later on that you should try to count movements. (Close to the end of pregnancy - can be an early indicator of distress.) For now, just enjoy them when they happen, and keep in mind too, that if you have a busy day, you will likely miss a lot of moving, which might make you worry that it isn't happening. My baby is most active when I am quiet - just before bed time he/she takes up tap-dancing! And now at 24ish weeks, I have strong kicks that others can feel too - your DH will probably love that when that comes. Not too long to wait.
And as far as the worrying goes - each and every one of us, I think, does that. Until you feel your baby move, (once the m/s has eased) the only "sure" indication that you really are still pg is the heart beat at the doctor's visits. I was relieved every time again, too. It's perfectly natural. Try not to stress to much - it sounds like everything is going beautifully for you. All the best!