Welcome to the forum!!
I have insulin resistance and I'm also 20 and my name happens to be Marissa, close but no cigar..

I know where you're coming from in a sense. I've gained alot of weight over the years and its incredibly hard to take it off. I've lost 63lbs so far but have gained 5lbs back. Congrats on the weight you've already taken off, you should be proud of your success so far.
I figured I'd share alittle bit of my story so atleast you don't feel alone
I'm here everyone here is really great you're in good hands I promise.
Again welcome to the forum.