If you feel weak, you are in good company with the saints of old. More so, you are positioned for God to grace you with his presence and use you for his purposes. Here’s a testimony from the Apostle Paul:
 So to keep me from becoming conceited because of the surpassing greatness of the revelations, a thorn was given me in the flesh, a messenger of Satan to harass me, to keep me from becoming conceited.  Three times I pleaded with the Lord about this, that it should leave me.  But he said to me, “My grace is sufficient for you, for my power is made perfect in weakness.” Therefore I will boast all the more gladly of my weaknesses, so that the power of Christ may rest upon me.  For the sake of Christ, then, I am content with weaknesses, insults, hardships, persecutions, and calamities. For when I am weak, then I am strong.
(2 Corinthians 12:7-10 ESV)
And a prayer adapted from The Valley of Vision:
O Spirit of God,
Help my infirmities;
When I am pressed down with a load of sorrow,
perplexed and knowing not what to do,
slandered and persecuted,
made to feel the weight of the cross,
help me, I pray to you.
If you see in me any wrong thing encouraged,
any evil desire cherished,
any delight that is not your delight,
any habit that grieves you,
any nest of sin in my heart,
then grant me the kiss of your forgiveness,
and teach my feet to walk the way of your commandments.
Deliver me from anxious care,
and make me a happy, holy person;
help me to walk the separated life with firm and brave step,
and to wrestle successfully against weakness;
teach me to praise, adore, and magnify you,
with the music of heaven,
and make me a perfume of praiseful gratitude to you.
I do not crouch at your feet as a slave before a tyrant,
but exult before you as a son with a father.
Give me power to live as your child in all my actions,
and to exercise sonship by conquering self.
Preserve me from the intoxication that comes with prosperity;
sober me when I am glad with a joy that comes not from you.
Lead me safely on to the eternal kingdom,
not asking whether the road be rough or smooth.
I request only to see the face of him I love,
to be content with bread to eat,
with clothing to put on,
if I can be brought to your house in peace.
(“Weaknesses” Pgs. 188-89)