Warning : this is a depressing post. Not worth reading, unless you think you can help.
Existence is lonely. Humans may be social animals but at the end of the day (or the life) we are all alone. You may feel close to people, your parents, your spouse, your kids, but there comes a time when they leave (death or otherwise) & suddenly you are so lonely. I think that loneliness you feel is your ground state, the affection (or attachment) had actually excited you to a new energy level & mood. When you die, you die, everything else is disturbed only for a little while, like ripple in a pond, which soon settles back into its normal steady state. Similar to this, life returns to normal after a while even without you.
Hence your loneliness, that only you can deal with.