I feel your pain. My sister is always on me about my weight. And I will admit I have yo-yoed with my weight for years. But my sister had been probably well into the 300 for a good 15 plus years (during this time still on me about my weight). Then a couple years back she got the weight lose surgery. Now she acts like she has all the knowledge about the right and wrong way to lose weight. Plus we always hear about how this hurts her stomach and that hurts her stomach. She still eats a good bit of fast food and other such items. I use to let it get to me, but why should I let her make me feel bad?
You need to lose weight because you want to. I agree that your family members might think they are helping, but I would tell them that you have decide to go a different route with your weight lose and they should support that. I do not think surgery is the best option. In my opinion it causes more problems than solutions.
Keep your head up and keep working for YOU!