Hi, could you begin by explaining to them that you want to open up to them but then tell them what has happened to you in the past and what you are afraid of as well. Perhaps then they can be a bit clearer to you on how they be able to help you and give you some assurances if you need them.
I know this must be a really scary time for you anyway with everything going on for you, but you are making exactly the right desicion in wanting to reach out, that shows real strength and courage just hold onto that and try to take that first step in starting to tell them how things are to give yourself the chance of getting the help you really need.
And it's a great idea to write things down first, that way you may to be able to express yourself better and not leave anything out as well, so as they can give you some help that might better suit where you are at right now.
Best wishes
Alison