Heart issues?

Since yesterday I’ve been experiencing high heart rates and feeling like I’ve got flutters in my throat and chest this only started yesterday at work and it’s carried on into today it’s making me extremely unsettled and scaring me I have early hashimoto’s my heart rate is resting in the 50’s and when I walk around it’s going up to normal 70/80’s but I keep getting random burst of it going to 120/130 and my heart feeling like it’s thudding and fluttering spoke to doctor yesterday he said it could possibly be related to my thyroid as my recent tsh went from 2.2 to 0.80 and said it could be a hyper swing as it’s only been happening since yesterday I’m un medicated as still in normal ranges after nearly 2 years now he’s ordering me a holter moniter to wear for 24 hours to check theirs nothing else’s going on and to make sure it’s the thyroid causing it and not something more serious but that’s worried me even more now. Does this sound like it could be thyroid related has anyone else had this happen to them?