Would you be worried?

I'm a stm and will be 19 weeks tomorrow. I started feeling small movements at 18 weeks, and I think I felt 1 kick. For the last 3ish days I really haven't felt much movement. If I felt anything I questioned if it was baby or just gas or something else. I have been using my fetal Doppler and getting normal heartbeats. Yesterday when I used it I had trouble finding the heartbeat but it was super low in my pelvis right above pubic bone, and it was still hard to find, only got it in one small spot. Overnight I woke up panicking a little because I thought I should be feeling more movement but I'm not and this morning when I used my Doppler the heartbeat was in the same spot. Still there just super low. My worry is baby is so low, it's really hard to find the heartbeat, she hasn't moved, and I'm not feeling movement. I'm mostly worried she hasn't moved. I should also mention that I have an anterior placenta.

I did lose my last pregnancy at 21 weeks, and I only knew something was wrong because I stopped feeling movement for about 5 or so days, after I started feeling it regularly. So the lack of movement is very triggering to me, I don't know if that's why I'm worried or if I really have something to be concerned about. I have a scan on Monday but it's driving me insane having to wait until then.