nurse said my pulse was 136??? 18 weeks

i know that’s not normal. i was a little nervous for my appointment but i didn’t think it would be that high. i always feel like my heart is racing or just beating really hard but i’d check it and it would feel normal. my midwife was finding baby’s heartbeat with the doppler and said it was hard to tell which one was baby’s and which one was mine 😳 they didn’t say anything was bad about it but is there any reason it could have been that high? i do have frequent anxiety attacks since becoming pregnant.