new to this ttc baby #3

hi ladies, I'm new to this and just join this group. I'm hoping someone can help me out being that I have thyroid but was never giving any medications and was wondering why.... I don't feel any of the symptoms but I do have irregular periods. I want to know what are my chances on TTc baby #3. I had so much hope I wouldn't have any issues being that I have two but joining this my hope has change especially since I read some of the females here have been on medication for thyroid and are having issues....