Nothing is wrong with you; you have experienced a major loss in your life, and it would be surprising if you weren’t reacting like this.
The most important thing I can tell you is to assure you that God understands your grief. He also understands your feelings, which to you may seem contradictory and confusing. But they aren’t contradictory or confusing to Him, because He knows what you’re going through. In fact, one of the Bible’s most comforting truths is that God understands just how weak and frail we are—and yet He still loves us. The Bible says, “As a father has compassion on his children, so the Lord has compassion on those who fear him; for … he remembers that we are dust” (Psalm 103:13-14).
Although your email doesn’t go into detail, I suspect you have been deeply involved in your husband’s care, perhaps for years. Now all that has ceased, and although you’re thankful that his suffering has ended, a major part of your life has changed. Now that he’s no longer with you, you even may feel useless or abandoned.
But you aren’t! God has other plans for your future; ask Him to show you. And in the meantime, take comfort in the knowledge that your husband is now free from all the pain and limitations of this life, and is safe forever with Jesus. And some day you will be also.