are these symptoms related to cancer or am I hyper or hypo?

Hi i am new to this site and need some advice please.
i was diagnosed with pap carcinoma in 2011 and had mu surgery in may and august 2011.
i had my RAI scan in November 2011. i have been doing well every since however
when i had my follow up neck scan and thyroglobulin test in May 2012, the radilologist notice i hd a swelling at the back of my throat and ordred an MRI scan to be sure which proved inconclusive as he suspected it was a cyst but my thyroglobulin levels were a bit high so they wnat me to do a PET scan .. and i am frightened and scared stiff !!
my children are young i look at them and just break down.

when i went of my thyroxine for the test i was able to function well and go to work etc. but since i got back on it i have been through such a difficult time.
i have hot flushes on my legs, arms and ankles, chest etc, i have heart burn, very cold chills,ringing ears, burning / tingling tongue, sometimes feels like something is stuck in my throat and i have got no appetite at all, tingling on my back.

a few days ago i had heart palpation and had to be rushed to the A& E but my heart trace was fine but blood test revealed i was hyper. so doctor said to reduce my thyroxine meds from 150 to 100 but consultant said 125mcg.
i however decided not to take it for a few days and start it off slowly from 75mcg , today i took 100mcg and plan to take 125mcg tomorrow.
but these symptoms persist and worry me
i have hot flushes on my legs, arms and ankles, chest etc, i have heart burn, very cold chills,ringing ears, burning / tingling tongue, sometimes feels like something is stuck in my throat and i have got no appetite at all, tingling on my back, some body aches, constipation, back aches, right lower abdomen discomfort or fullness . i had felt some of these symptoms about September 2011 and thought they were linked to cytomel of hypothyroid at the time but now i am just not sure. has anyone got any similar experience?
Many thanks