How do I play this note in my music?

I am learning to play this song but the very last note is really confusing. (I play double bass) so on bass clef it looks like 2 quarter notes put together. Like, one bubble is on g, and the other is on d and it has 2 circles at the top of the note then it has a little diamond on line A then another diamond on high D. then its like 2 fermatas on the top and bottom of the note..