What can happen to me if i was diagnosed with hypothyroidism, medicated but i stop taking the medicine?

It may worsen: It depends on the cause of your hypothyroidism--since sometimes it can resolve on its own. However, typically, hypothyroidism is permanent and requires lifelong thyroid replacement medication. If you stopped your medicine you will most likely become hypothyroid again fairly quickly. Talk to your doc about how to restart it and when to get retested.

Depends on severity: Did you have symptoms of hypothyroidism before you started medication? Common symptoms include weight gain, fatigue, hair/skin/nail changes and others that could be looked up online. If you had symptoms before you began the medication then I presume you will eventually have the same symptoms return. Check in with your doctor for blood work and let them know what has has happened, easy fix :)