Dear Jules,
Please post your thyroid test results. TSH, FT3, FT4, antibodies (whatever else you have). That will help in answering your question.
If you have Graves Hyperthyroidism then medications like carbimazole are needed to slow the thyroid back to normal to avoid complications like heart failure and stroke -- weight loss is common with hyperthyroidism and many will regain some of the weight as the thyroid is normalized.