My period has dissapeared for almost 6 months now (not pregnant) my mom has underactive thyroid and hormonal inblanaces should I see a doctor?

Yes. There are many possibilities to why you're not getting your period including other hormonal disorders. An exam and blood test will usually get you an answer.
YES. I believe you should know the facts: the loss of menses is most commonly attributed to four hormonal disorders: 1. Hyperprolactinemia. 2.Hyperthyroidism. 3.Pcos. 4too much adrenal steroids. If you have been dx'ed with hypothyroidism, you might be receiving too much. A TSH as suggested by others is necessary. As is the prolactin. But hypothyroid states, untreated, are associated with heavy menses!
Yes. 1 in 10 women will develop a thyroid abnormality and family history of abnormal thyroid function further increases that risk. Abnormal thyroid function can certainly interfere with the menstrual cycle. It would be appropriate to have your TSH checked (at least), considering your history. So, yes you should see your doctor.