Your daughter is probably worrying about the next step of starting "big school" this fall and being away from you. Begin talking every night about what school will be like, going through a typical day from the time your daughter leaves home until you pick her up or she gets home on the bus. There are many books available about starting kindergarten; check with your public library or a bookstore and get several to read over and over between now and the first day of school.
Call the school your daughter will attend to find out what hours the building is open. Take your daughter to visit now when there are few people there and walk through the halls and look into the classrooms. You will want to do this several times over the next few weeks. Be sure to take time to play in the playground. Meet whatever staff members are there and introduce your daughter to them.
Talk with the principal about your concerns. Ask him to place your daughter with a teacher who will be loving and understanding if she has separation problems this fall. Also talk with the school counselor and work out a plan ahead of time to assist your daughter if problems do come up.