So sorry to hear about your dad, and that might explain your feelings. Must've been terrible to find him.
Regarding the feeling that all you have to look forward to is kids, I think some women get fixated on dedicating their lives to children alone but in order to truly live life and enjoy it, you need to understand that this is YOUR life so do other stuff like travel; hobbies; see friends; make other people happy; volunteer etc. As you're quite young, you have SO much to look forward to cos by the time your kids leave home (when you're in your 40s) you can do all sorts: travel and stuff so you should feel quite excited. Life is what YOU make it. Don't just think 'well, this is it I guess; cooking dinner for the OH and baby-making for the rest of my life'. God no!!! There's so much more to life and if u want to ensure your children are happy, you need to lead by example and show them that you can enjoy life and live it to the full.