What Causes Irregular Heart Beat Along With Chills?

I have hypothroid for 10 years. I take .75 levoxly on an empty stomach daily. I also have bradycardia. my resting heart rate is 48beats per minute. I am 64 years old and relatively active. My diet is NOT loaded with junk food. Recently I ve notices more irregular heartbeat, sluggishness and cold skin. My tsh FT4 reflexive was done yesterday, it is 3.760 My Thyroid stimulating tsh was 4.260 She says this is normal. Should I do a follow up with an endocrinologist?