Hi fellow Feb mum!
I posted virtually the same question a week or so ago, so it must be about now that this happens! I agree with the growth spurt thing, as my belly has grown a bit since a few quiet days.
I got worried too, but after a few days, he or she was back on track. I found playing music through headphones on my belly got bubs moving - and taking some time out to really concentrate on your baby's movements, while lying down.

My ob said it's not until 28 weeks or something where you should feel movement regularly - before that not too worry too much.
I'm sure all is fine, but can understand your concern.