Kitty,
You
are not being a baby.

You're just having practical thoughts, I have them too even though I have my DH. I think about the what-ifs and it actually helps me to be more thrifty.
I was a stay at home Mom until about 12 years ago. I haven't saved all that much for retirement yet so I'm trying to do it now because I could
need to retire any day now (thanks to MS.)
All we can do is keep on going, saving if we can and try to be healthy outside of MS.
If DH died young, and I live to my 90's (like my Dad did) I know I wouldn't have enough to take care of myself for that long. I might be able to if I can keep working until my regular retirement age (17 more years!)