You need to stop worrying about getting your family's approval. If you try to make everyone else happy you will end up being miserable. If you are happy that is all that matters. You need to be happy with your decisions at the end of the day, regardless if other people agree with them or not...
Keep taking the tests. However, because you think you are pregnant you are stressing your body out without even realizing it (I did it too and was late many times...though my husband and I were trying to conceive). Just try to relax and not think about it.
Each state has their own child support table. Which state do you live in and I might be able to help? It would also depend on the number of children and age(s).
Keep records of him contacting you and of you telling him to stay away; then file a protection from harrassment order against him. As far as him contacting your family/friends, there's nothing you can do about that. He can contact whomever he wants and if your friends/family doesn't want him...