sounds like you may need to take it apart and square up your blocks. it is important to have squared blocks all the same size before trying to construct; also, with star points it is usually a good idea to press the seams open this reduces the bulk where they come together. check out the quilt in a day web site (elenor burns) she has a couple good tutorials for putting together stars and how to (spin) the center so it all lays nice and flat.