Baby movements a concern?

im 36 weeks pregnant wth my second child , wth my first i used to always wonder and worry whn i didnt feel him move that much.. he ws born almost 6 pounds and is a healthy 2 year old now,, but i hv concerns abt ths baby as i ws readng a book and i said if i ever felt vigourous unusual mvnts frn the baby like a sudden panic movmnt then i shd be cncrnd.. well i have felt those before and t ws weird bt i nvr told my ob. i see my ob twice a week now and am put on the monitors and evrythg seems fine so far but what could it mean.. what kind of promblms are there that hav to do wth baby moving in a sudden panick pattern or sudden quick hard jabs or kicks. i wonder now cuz on my last visit they tld me i have strep b ...