In my experience when Muslims speak of “low iman” it is not actually a problem with their faith, it is just that they are depressed and their depression makes them feel abandoned and unspiritual.
If you think you are depressed, then remind yourself that it is your psychology that has changed, not your relationship with God.
Even if you get no satisfaction out of the acts of worship, continue to perform them as a proof of your faith in God.
It is good to worship God when it makes you feel good.
But it is even better to worship Him when you have to force yourself to do it, because remaining steadfast despite difficulties and turmoil is what distinguishes the best believers from the average ones.
If you feel as if God dislikes you and has turned away from you then realize that this is just your depression making you think these thoughts.
Always think of God the way He describes Himself (the Most Compassionate, the Most Merciful), regardless of how you feel.
A saint is just someone who has reached a state where nothing that God does to them will reduce their love for Him.
Even though they know that God is fully in charge of the universe, when they suffer they do not blame God for it and they never think negative thoughts about Him.
They keep facing Him and striving toward Him regardless of what storms He sends their way, knowing that He is only giving them opportunities to prove their love for Him.