Stubborn baby

Does anyone else baby move constantly for multiple days then other they just don't or they are very low and light flutters or feel like they are just pushing on on part of your stomach but not having big movements? I'll be 30 weeks this Saturday and I have an appt on Monday so I'll ask my Dr then. This is my first baby I have a miscarriage a few years ago and just feel super paranoid this whole pregnancy. I talk to him and poke or rub him all the time it feels like but he doesn't always respond. My Dr told me to start counting kicks the other week and I feel like I have not started to hyper focus and get worried when he doesn't move alot. I have a doppler at home and his heart beat is always normal but sometimes hard to find like this morning it was low down on my belly unlike other days it's higher up in my stomach. The few times I have felt h the flutter are just lower down and not high up like they where last week. I'm just scared and I am pretty sure he is okay just didn't know if anyone else has have this?