Ex is 5 weeks pregnant, suddenly last night she decided I was to have nothing to do with the baby and I don't know my rights, I feel small

Sam, you need to get her to put that is writing, a formal letter, that will give you protection with CMS and otheres who she may approach to cause you problems. When the baby is born need to ask for a paternity test, you may need a Court Order for this if she objects - this can then determine if you are the father and if you have any legal responsibility for the child. If the Child is NOT biologically yours, you have no legally enforceable obligations. If the child is yours you need to sit and think, very carefully, about how to proceed further. If you wish to be a father to the child, then you need to accept the full responsibility that comes with that, which will mean financial support until the child is out of full time education - that could be up to 20 years and you should insist that your name goes on the birth certificate - again, this may require a Courts' Order to enforce this. If a mother refuses to put a fathers name on the birth certificate then you can ask a court to enforce this under a "declaration of parentage" as defined under S55A of the Famnily Law Act 1986.