Wa'alaikumassalam! Honestly lendir coklat macam tu after intercourse bukan uncommon sih, especially kalau ada sikit bleeding atau old blood coming out, tapi since you're further along (I'm assuming based on you checking baby movement), better safe to text your doctor or clinic just to confirm everything okay, takut ada apa-apa kan. One of my mum friends had the same thing around 7-8 months and doc said it was fine, normal cervical changes, tapi dia still checked je to be sure, so don't worry tapi jangan skip the call to your midwife/gynae, they'll put your mind at ease! Baby gerak normal is a good sign la, tapi it's always better to ask your healthcare provider directly especially during pregnancy.