No weight gain or hair loss, still hypo?

Is it possible to be hypo without the classic symptoms ie weight gain, hair loss, intolerance to cold, constipation etc?

I DO have lower body temp (borderline) and low pulse rate. I am NOT tolerant of heat, have normal bm's and no weight gain. Is it possible to still be hypo and have the symptoms I do? I am sleeping fairly well lately. I have been taking 225mcg of kelp every day but skipping a day once a week or so and using Redmonds Sea Salt on my food. Still the heat is now intolerable. When I was in my teens and 20's neither the heat nor the humidity bothered me regardless of how hot it was.

I ordered Xymogen MedCaps T3 and will see if this will help.
Can anyone lend their 2 cents about this? BTW my last tsh reading was 5.45 and I did not get the reverse t3 which I will next time.