first time mommy

i just been going a bit crazy because i havent had an ultra sound since i was 12 weeks, ill be 18 weeks tmr, & my next ultra sound isnt until 21 weeks. i just wanna know is my baby ok? does it have a heart beat still? is it growing properly? i havent had any syptoms & i honestly dont feel pregnant. i been having some pain here & there or like uncomfortable feeling , but no bleeding or nothing.. i just wish i could know how my baby is doing all the time. any advice ?