I'm the same way with even my 2 year old now lol. I have another due when she's three and I'm so worried about this!
Well, lots of new parents have this fear especially with a first baby and truth is that with a new baby, you should be somewhat cautious. Our pediatrician said not to go to large social gatherings the first month, keep baby in infant carrier at times of big crowds, encourage people to touch baby's feet rather than hands. We did this with our first. But whew, our second? Baby went EVERYWHERE. LOL I think they have commercials about first baby fear and obsessing over germs and later babies being thrown into the arms of anyone that will hold them. LOL
I'm really sorry about your dad, hon. That's a big loss and certainly will impact you for a long time. I'd also be on the look out for anxiety or post partum when you give birth. This happens to many women and you need to be up front and tell your doctor. It can really make the start of your child's life with you much stressful and less enjoyable than it can be.
Remember too that babies who are nursed get some immunity through you. :>) good luck