Go to the One who brings thanksgiving...

Isaiah 51 “Listen to me, you who pursue righteousness,
    you who seek the Lord:
look to the rock from which you were hewn,
    and to the quarry from which you were dug.
² Look to Abraham your father
    and to Sarah who bore you;
for he was but one when I called him,
    that I might bless him and multiply him.
³ For the Lord comforts Zion;
    he comforts all her waste places
and makes her wilderness like Eden,
    her desert like the garden of the Lord;
joy and gladness will be found in her,
    thanksgiving and the voice of song.
The Psalmist here calls on us to look to the Father of Faith as an example.  He trusted God, even when they were barren and God blessed and comforted him.  If we cannot find a reason for thanks, it says something about our faith or lack thereof.  He is great. He is good. He is our solid Rock.  Go to Him, seek Him, trust Him, and you will find a reason for thanksgiving.