Chronic Migraine, Memory Loss, Twitching In Eyes And Loss Of Appetite. Taking Synthroid For Hypothyroidism. Cause?

I have not been feeling like myself latlely. I feel tired all the time. I have a constant migraine throughout the day, the pain is usually at a 3 all day but at times gets to an 8. For the past weeks i have been getting this pain in the back of my right arm, it feels like alot of pressure and hurts badly. Today it started in my left arm. Also, for the last 2 days my left eye has been twitching, it last for about 3 seconds, about 5 times a day. I also have a loss of appetite, and thats not like me. Another thing is my speech has not been normal the past months, i will be talking and words come out of my mouth that i didnt intend to say, for example ill be looking for my shoes and when i go to say 'has anyone seen my shoes?' my sentence comes out as 'has anyone seen my tv' or any random word and it happens multiple times a day. Im also having memory loss. Im only 18 year old female. Im also diagnosed with hypothyroidism and take synthroid.