Could severe dehydration affect the results of a home pregnancy test? and could severe dehydration also cause a missed period?

Severe dehydration?: Please forgive my frankness. Who told you that you had "severe dehydration?" If you are up and about and wondering if you are pregnant, you are going to get something to drink before dehydration becomes severe. "Severe dehydration" kills neglected children and disabled people. Look for some other explanation for your missed period; I hope it is what you want.