Hardest Part of Being a Single Parent

Hi! I was debating the other day that since I was a single parent I didn't think that loneliness was the hardest thing about being a single parent, that the financial responsibility is. a) do you think "loneliness" includes "financial responsibility"? or do you think that is separate? b) what do you think the hardest part about being a single parent is? Is it one of those 2 or something else?