Quivering heart??

[Caitlyn6]

For about 6 weeks I have had a feeling that my heart is quivering. I had a 24hr ecg which the gp rang me to say was normal. It coincided with me starting a higher dose of Thyroid medication so I was told I could drop the medication back down but the quivers and unsteadiness are still there. I am at a loss as to what to do now. I don't feel dizzy with it. It's a new symptom to me. I don't feel quite right but I have been told before my heart is ok when I have had palpitations, tiredness etc. I am 50, diabetic type 1, MS and underactive Thyroid and low ferritin (on ferrous fumerate- it's currently 14)I am seeing my GP in two weeks time. Currently on Perindopril and bisoprolol. I also posted recently about HR going high in exertion. Thanks for any advice. I had an echo back in February which was 55%. I also have a low immune system due to MS treatment but all is fine with the MS.