Its normal for symptoms to come and go throughout your pregnancy. Your odds of miscarrying are greatly reduced with how far along you are. Try not to worry yourself to much I'm sure things are fine. Like mentioned above if it would help give you piece of mind you can buy a doppler so you can listen to babies heartbeat.
I got me a fetal Doppler to and now that he moves all time I still use it lol. I just love the sound of his heartbeat :)
It is very scary! But try to stay calm :) getting nervous will put stress on ur baby! Stay positive! I invested in a at home heart doppler so whenever im worried i can always rassure myself. Stay strong :) make sure to update us! Good luck momma :)