As you told that you are suffering from hypothyroidism
and have a very high level of TSH
14.8. This is really very high level and the only treatment for this is to take the medication properly and in proper dose so that this can be controlled. Other problems which you are suffering from can be because of this hypothyroidism only and once you can control this problem other things will also go off.
Now as you told that you are not able to take the whole tablet and have some problem with that, than I would suggest you to consult your doctor and ask if it is ok to take medication in multiple doses and 2 or 3 times in a day or you can ask for some preparation which can be taken more frequently.
You are already on medication for palpitation
and hope this help you in controlling your condition, but you have to take medication for this hypothyroidism and after controlling this your condition will improve.
Thanks and take care.