I have been taking Levothyroxin (Synthroid generic) for about 5 m...

I have been taking Levothyroxin (Synthroid generic) for about 5 months. I started on a low dosage and have been taking 75 mcg (which turned out to be the right dosage. I turned 59 years old in July and I had been gaining weight.Nothing startling--a few pounds a years that added up to about 50 pounds over time..I am losing weight now. The side effect I am most concerned about is a an inarticulateness I seem to have developed since I started taking the medication.I can't sepak civilly to my son who also turned 20 in July. I just want to scream at him all the time. Is this a side effect of Synthroid? I don't think I have been losing my hair, fortunately, but it is dry and brittle...