When you give charity for the pleasure of your Lord and in your heart you get doubts about you gave/giving too much or you could have used the money else where then know that that’s the Shaytaan (devil) trying to take away the good you have done.
Never regret giving money to a humanitarian cause for the sake of Allah. You will see its benefit in this world and hereafter. Better still you will have gained the Pleasure of your Creator by giving.
Nothing can be better than knowing that Allah is pleased with you.
Spend on good causes wherever possible its a sign of Imaan:
“By no means shall you attain Al-Birr (piety, righteousness, etc., it means here Allah’s Reward, i.e. Paradise), unless you spend (in Allah’s Cause) of that which you love; and whatever of good you spend, Allah knows it well.”
(Quran Surah 3, Verse 92)