Hi, I agree that the thyroid gland if you continue to gain with no apparent reason rapidly i would suggest going to the doctor and asking for a thyroid test.

Sorry it is bothering and upsetting you so bad, and hope that you can find a reason for the weight gain, 6 pounds seem maybe a little bit of water weight.

I do not know you well but do you have any eating disorders that would add to the worry of the weight gain? I was just wondering I gain and loose and if it is overly upsetting to you and interferes with your daily functioning perhaps a counselor or therapist could help with all the stress over the weight issues.

Hope you are feeling better,
kk101