I am not married but I have seen how my friends got anxious before the wedding. It's okay to feel like that.
Life is difficult in itself and marriage is difficult. You should be happy that the love of your life has committed to you and is marrying you.
About the absence of your dad in law, make sure you let him know how it makes you feel bad that your dad in law won't be there for the wedding, the fact that you are feeling bad too will let him be strong. If you tell him that you want him to enjoy just as much as you would then that wouldn't help how he feels. (Just my opinion but don't worry, dream about the future you will have together. By the way Congratulations!)