Baby's hr fast

I am 12w4d and had to go back for a follow up dr appt d/t me having the flu last week. Last week hr was 190 and dr said it was because I had a temp. But this appt and every appt I have been too the hr has been 170ish, is this normal? I have even stopped drinking caffeine except for occasional pop bout once a week. She said next time it should be down but I'm nervous and scared