Death is not the end of all.

"Then I saw a great white throne and him who was seated on it. The earth and the heavens fled from his presence, and there was no place for them. And I saw the dead, great and small, standing before the throne, and books were opened. Another book was opened, which is the book of life. The dead were judged according to what they had done as recorded in the books.”
(Rev. 20:11-12 [ESV])

The most wonderful thing would be to see them in heaven, of course. I think good advice is to be trusting of others and questioning of yourself. Leave your loved ones who have passed from time to eternity in the care of God. Pray to God for them once or twice, and rely in faith on Him who has conquered the power of Death. You can also take comfort in the fact that with God there are no dead. With Him all are alive, because He is not bound by the laws of this world.

Fear not, I am the first and the last, and the living one. I died, and behold I am alive forevermore, and I have the keys of Death and Hades.
(Revelation 1:17d-18, ESV)