Downcast

Why do i feel so discouraged right now!?
I was incredibly encouraged this past weekend at the BIG bible study and then on Sunday morning as well, but now i am just heartbroken with no clue why!

Psalm 43

1 Vindicate me, O God,
and plead my cause against an ungodly nation;
rescue me from deceitful and wicked men.

2 You are God my stronghold.
Why have you rejected me?
Why must I go about mourning,
oppressed by the enemy?

3 Send forth your light and your truth,
let them guide me;
let them bring me to your holy mountain,
to the place where you dwell.

4 Then will I go to the altar of God,
to God, my joy and my delight.
I will praise you with the harp,
O God, my God.

5 Why are you downcast, O my soul?
Why so disturbed within me?
Put your hope in God,
for I will yet praise him,
my Savior and my God.