ehirsch83- Are you presently taking thyroid replacement pills? Have you had your levels checked recently ( you mentioned no insurance...)? There are so many reasons for missing periods that may or may not be related to training. With your health history you really need to see a dr . I don't know what a physicians' visit costs , but you are investing so much time and effort into your health via exercise that I think the financial cost of a drs visit is worth it.
Keep us posted.........