Following is a link to info on postpartum thyroiditis. There is an explanation of when it occurs, how long it typically lasts, and the possibility of a permanent problem of hypothyroidism.
http://www.mayoclinic.org/diseases-conditions/postpartum-thyroiditis/basics/symptoms/con-20035474
Based on your symptoms, when you see your doctor next week I think you need to request those tests and then from the results you will be able to determine the next step you need to take.
I agree with des900 that your problem may stem from hypothyroidism, so I would actually start with doing some testing with your PCP first. I would request the tests for TSH, Free T4 and Free T3 (not the same as Total T4 and Total T3), Thyroid Peroxidase antibodies (TPO ab), and if TPO ab is negative then Thyroglobulin antibodies (TG ab). The latter are to check for Hashimoto's Thyroiditis. I would also request an ultrasound test for the thyroid gland to see if there are any nodules. Once you have this information you can better determine if you need an ENT or a good thyroid doctor, which does not necessarily mean an Endo.
When you have test results please post them, along with reference ranges shown on the lab report and we will be glad to help interpret and advise further. Even more importantly we will need to know about all the symptoms you have, since symptoms are the most important indicator of your thyroid status.
If you have hypothyroidism its possible that your thyroid gland get enlarged due to increased TSH levels. So get tested for your TSH, Free T4 nad Free T3 and if TSH value is raised like over 10 then most probably you need to start thyroid hormone replacement treatment.