What a terrible ordeal to go through right before vacation. I'm so sorry all of this happened. You really have two issues you need help with: the incident with your ex-boyfriend and your Disney trip. This is a great place to get help with both, but you really need to get someone on your side with the ex situation. If you don't have a family member that will help you or any friends to speak of then I'd highly suggest calling one of the domestic violence hotlines for other options. You can also visit your local church. I'm not sure which part of the country you live in, but churches here (the south) are more than happy to help anyone in your situation (whether they're a Christian, atheist, agnostic, or whatever--don't let your religion stop you from seeking help). A bigger church would be better than a smaller one, probably, because they have more resources. I would get this situation settled to the point where you'll feel safe when you get home before you do anything else. You'll be worrying your entire trip if you leave the situation open when you go. And be sure you completely sever any communication with your ex. I know there must be a lot of heartbreak over this, too, but you have to make it extremely difficult for him to find you right now.
As far as the Disney trip goes:
I would call to see if you can push everything back a week or two, so you have a little more time to get things in order before you go. If this isn't an option then leave everything as it is, and just do the best you can before you go.
I think the money you have for food will likely be more than enough. I would make a detailed budget of where that money is going to go. Then I'd stick to that budget when you get there. List out the total money you'll have to spend, then itemize all those little things you mentioned in the first post. Maybe even put the money in individual envelopes, and put them in a very safe place, so you know when you've run out for that specific category. I'd budget a set amount for the kids to spend on treats each day--$5-$10 or so. Tell the kids that it's their money at the beginning of the day. They'll usually spend less and be more careful with money if they know that it's "theirs."
Since you have a small appetite, consider sharing meals with one of the kids. I know lots of people have given tips on meals to eat at Disney World, but you're not actually going to DW at all, right? I'm not familiar with Universal, but see if there are places on these boards that serve larger portions of food (like the Flametree BBQ place in AK). You can order two meals here and split to save money. Also, the one night you're at POR you should consider ordering the make your own pasta. It is a ton of food. I'm a small eater, but I seriously could have made about 5 meals out of that one box of food.
Another option is to consider having two big meals, and eating a snack for the third. I always budget for three full meals at Disney, but we never eat all that food. You could eat a big breakfast around 9 or 10 and probably just snack for lunch. Then eat dinner around 5 or 6. Or you could do the opposite plan and just eat several tiny meals throughout the day. Sometimes kids eat better in small amounts when they're excited.
You can stock up on little souvenirs and snacks before you go. The $1 Tree has lots of things like candy and stuff. You can get little pouches that you add to water to flavor it for days in the park.
I really think you'll be fine on money. I am very type A, and I've budgeted our trip like crazy. It's just two adults going on ours, but we're eating one Disney meal and one regular table service meal at a nicer restaurant. We're staying for 8 days, and I'm budgeting a little less than double what you have for the whole trip. You'll be fine on money. Just plan it out, and then take care of securing your stuff while you're gone. Definitely let the police know you'll be on vacation. One year I discovered that our entire street happened to be going on vacation at the same time. I called and told the police department and they immediately offered to send a patrol car around often. I'm sure they'll keep an eye out for you. Try to stay calm, and maybe spend some time watching
Disney Cruise videos on Youtube with your kids. It might get you excited about going again!