My husband is on disability... he has lupus, tourette's, autism, bipolar, borderline personality disorder, social anxiety... he gets $674/mo.
Unless you live in a state that adds money to the federal disability rate, that's all you'll likely get too.
I don't have a job either so there's two of us trying to make it on that much.
We live on food pantry... you're not qualified for food stamps if you have disability. Most churches have a food pantry of some sort.
Our housing is $350 a month but this doesn't include our electric bill.
Some things you can do: Use public library internet, or if this isn't possible get a landline and cut your internet to dial up. I know it's tough but it saves a lot of money. Cable will be out of the question unless your dad will pay for stuff like that for you.
We get internet through the local private college who lets us use their public network.
Tip 2: Keep your credit card debts to a bare minimum... you don't want to be saddled down with trying to pay off cards every month. If your dad will help with the cost of anything (none of our family would help us unfortunately) accept that help.
You're not going to get enough to really support the standard of living that most Americans expect. We don't have a texting plan on our one cell phone. It's cheaper than a land line but we have to share the phone between us. That's $50 a month. You will likely need some help with food costs.