M.B.
You do need to make sure they run all the thyroid tests - Free T3, Free T4 (they MUST run Frees and not Totals, as the Free is what's bioavailable), TSH, anti-thyroglobulin antibodies (anti-TG) and anti-thyroid peroxidase antibodies (anti-TPO). You should get copies of all the tests they have run and not just accept "normal" - you need to know where you are in the ranges and exactly what tests they ran. If they only ran TSH, that is useless, since TSH is a pitutitary hormone and doesn't reflect thyroid function - it reflects feedback (levels of Free T3 and Free T4) from the thyroid, but doesn't tell you what your thyroid is really doing, in particular if you have antibodies.
The inability to gain weight is a sign of hyperthyroidism, but it's also a sign of diabetes. And, if the doctors won't run the right tests, you can get them run yourself from a variety of reputable online resources that use local Quest and Labcorp locations for the blood draw.
And, if they are abnormal join the Texas Thyroid Yahoo group to find a good doctor:
http://health.groups.yahoo.com/group/Texas_Thyroid_Groups/
You do also have another problem if your husband is making fun of you - it's really not acceptable IMHO for a husband to not take his wife's concerns about her health seriously - honestly, he should be helping you with the problem and not mocking you.