Hi Jeremy -
I am sorry to learn of your father’s death.
It is common for people to dream about loved ones who have passed on. Typically the dead visit us in our dreams with regularity in the period immediately following their transition, and then as time passes, the dream visits decrease in frequency. I think it is clear that you miss your father. Your dream shows that you are thinking about him and some of the memories that you two shared together. Water in dreams almost universally represents emotions, so I think it is also significant that your dream is set at the lake you two used to visit together when you were younger. We know your dream was emotional - you awoke with an actual tear running down your cheek.
The fact that your father did not appear when you called to him suggests that you have come to gripswith the fact of his passing on. Instead of you being able to see him, the dream instead shifts to his grave site in Minnesota. It is interesting that your dream pauses before showing you his grave. This suggests that you had to think about where your father really is - and that you acknowledged his death with the shift of the dream to the gravesite.
There are so many things we wish we could share with those who pass on prematurely. You would like to share the news of your girlfriend with your father - as represented by the photograph of her which you have placed on the grave.
Death is a great mystery. We don’t know if the dead can hear us when we speak - if they stay around and watch our lives and occasionally intervene to help us along the way. Many people feel they have been touched by those who have passed on - so maybe your father is with you in your heart and your thoughts. We wish you peace in your time of bereavement.