Definitely get checked out tomorrow if you can, they'd much rather you go in with everything still okay than anything else. You'd certainly wouldn't be wasting anyone's time, and even if they thought so, fuck it, they're your baby and their health is the most important thing. Hopefully you're more at ease now that there's been some stronger movement.
I don't really have statistics. Actually it may not be helpful to share this, I'm not sure, but when my mum was having me I was growing way too slowly and was measuring 9 weeks at the dating scan; 16 or so weeks at the anatomy scan (I had some fetal growth thing. Can't remember the name now). Anyway when I was measuring around 23/24 weeks when my mum had reduced movements with me, went to get checked out and she pushed and refused to leave as she felt something was wrong and they were kind of shrugging it off due to how early a stage we went at (she sadly had a stillborn the year before so that might be been why she was so stubborn).
Anyway after refusing to leave until she was seen, she had an e-c section later that night and I wasn't given the best prognosis - far from it. Obviously I'm still here so I made it 
Never think you're wasting anyone's time. Ever. If you feel you need to go there, go, no matter how many times you've been before
I also need to say that it's not supposed to freak people out - just show that you know your babies better than anyone and if something feels slightly off for longer than usual than everyone else needs to take a backseat