This means there is an immune system attack on the thyroid. The ANA may be related to that (if a low titre) or may be a separate immune system attack.
Autoimmune thyroid disease does not mean the thyroid is not able to function properly, but full evaluation including thyroid function tests (TSH, T4) and ultrasound is usually done, then discussion w/ endocrinologist regarding any necessary medication.
The ANA is usually evluated by a rheumatologist to see if this is clinically significant or not.
If all else is coming up normal, given the weight loss and constipation would consider a gastroenterology evaluation.
THANK YOU for your advice. It was greatly appreciated.