I think many of us on this board have been in a similar frame of mind-- it's hard to get excited when part of you fears that your baby may not make it or may have a severe health challenge. Nobody wants to get their hopes up and then have them crushed, even if you weren't trying to get pregnant.
Hang in there and take one test at a time. If you've haven't been taking folic acid and/or eating your foods high in them, get on that asap-- that's a huge part of preventing occurrences of spina bifida. And I may be totally wrong on this, but I believe the higher rates of spina bifida are related to factors on the mother's side more often than the father's side (not to discount that factor, however). As well, nowadays, there are some forms of spina bifida that can be repaired while the fetus is still inside you that can greatly decrease the severity or side effects of the condition.
Feeling sick and tired are all good signs-- it means your body is doing what it should! Good luck and keep us posted!