Carolyn Hax: While grieving, ‘What are friends for?’ is not a rhetorical question
Once you’ve sorted this out, yes, do let your friends know you’re upset. Pick the one you’re closest to, though, and say it one-on-one. Again, talking vs. writing, if feasible. “I am wrecked about the funeral. It was awful. And on top of that, no one called me or checked in. I am sad on top of sad.” If friends did forget/lose track, then they’ll likely do whatever they can to see you’re made whole.