Hypothyroidism is one reason that our temp becomes low due to lack of hormones. It is sometimes difficult to get diagnosed if our TSH (thyroid stimulating hormones) are within the normal range (and doctors take no notice of clinical symptoms).
Our stomach can give us problems too and I've found taking some Apple Cider Vinegar in juice or water before or after meals can help as it supplies acid to enable protein to be dissolved. If hypo we can produce to little acid and that can give us unpleasant symptoms. Sometimes, because high or low acid are so similar in symptoms many doctors prescribe antacids.
As CarolynB suggests, get a print-out of your most recent blood test results from the surgery (we are entitled and they cannot refuse but some charge a nominal sum for paper/ink). Always get a copy for your own records and so you can post if you have a query.
If you haven't had your B12, Vit D, iron, ferritin and folate tested ask GP for a test and post these too.
We have to read and learn, unfortunately if we want to get improvements.
Hypothyroidism means we don't produce sufficient hormones to drive our metabolism normally, thus we can feel cold, slow pulse, fatigue, insomnia etc. There are about 300 symptoms altogether.