she makes me feel like I'm a burden
You are. She is not being paid for this, probably given no time, and you create an enormous amount of extra work. Those of us who do it (usually) do so because someone was kind enough to do it for us and we want future teachers to be competent.
I would like to feel welcomed and included
You are training to be a teacher. You need to learn to feel shat on :-)
Seriously this is a brilliant job but it is often fucking tough and thankless.
I am scared to ask her for help now
You don't ask your mentor for help with stuff you can get from other people e.g. navigating school/what the school day is like- you ask someone who is not busy, office staff or a kid.
You do need to ask a lot of questions and you can't afford to hold back. You even need to be a nuisance- this is expected. What you don't do is ask the same question twice or need hand holding. Try to be as independent as possible, but this will still involve a lot of asking the right questions. You will get criticised a lot and you will fail a lot- that's OK, we all did the same.
Spread the questions around, listen to the answers and accept when someone says they are busy. Buy your mentor a nice gift when you leave.