Why does my iman go up and down?

Your iman (faith) goes up and down because you are human, and Islam says this is normal. Faith rises with worship, remembrance and good company, and it dips with stress, busyness, sin and neglect. Even the Prophet's Companions felt it. The goal is not a constant high, but to keep returning to Allah and holding on to small, steady habits.

Faith is not fixed

The Quran describes faith as something that grows. It says the true believers are those "whose faith increases when His revelations are recited to them" (Quran 8:2), and that Allah sent serenity into believers' hearts "so that they may increase even more in their faith" (Quran 48:4). Most scholars say that iman increases with obedience and can decrease through neglect or sin. Whatever the exact wording, everyone agrees that the feeling of closeness to Allah changes from day to day.

The Companions felt it too

Hanzala, one of the Prophet's scribes, once told Abu Bakr he feared he had become a hypocrite. When with the Prophet ﷺ, he felt as if he could see Paradise and Hell, but at home with his family and business those feelings faded. The Prophet ﷺ reassured him that if their hearts stayed the same all the time, the angels would shake their hands, "but, Hanzala, time should be devoted to worldly affairs and time to prayer" (Sahih Muslim 2750). The dips do not mean you are fake.

Common reasons your iman dips

Busy work, study or family life that crowds out worship.
Sins, especially repeated ones, which can harden the heart.
Tiredness, stress, illness or grief.
Constant scrolling and entertainment.
Lack of Quran, dhikr or friends who remind you of Allah.
For new Muslims, the excitement of a new faith can naturally settle down.

What to do on low-iman days

ٱلَّذِينَ ءَامَنُوا۟ وَتَطْمَئِنُّ قُلُوبُهُم بِذِكْرِ ٱللَّهِ ۗ أَلَا بِذِكْرِ ٱللَّهِ تَطْمَئِنُّ ٱلْقُلُوبُ "Those who believe and whose hearts find comfort in the remembrance of Allah. Surely in the remembrance of Allah do hearts find comfort." Quran 13:28

Keep the basics: pray, even if you feel little. The Prophet ﷺ said the most beloved deed to Allah is the most regular, even if small (Sahih al-Bukhari 6464).
Remember Allah: a few minutes of dhikr or listening to the Quran. See What is dhikr and how do I start?
Make dua: ask Allah to strengthen your faith, in your own words.
Fix the cause: sleep more, cut back on distractions, repent of any sins and spend time with good people.
Do a good deed: charity or helping someone often lifts the heart.

For more on how to keep steady, see What is taqwa? and What if I feel nothing spiritual in Ramadan?

When it may be more than a dip

If you feel numb, hopeless or lose interest in everything for weeks, it may be more than a faith dip. Low mood and depression are health issues, not proof of weak faith. See Can I have depression and still have strong iman?

Key points

Iman naturally rises and falls, and the Companions felt it too.
Worship and remembrance raise it; neglect and sin lower it.
On low days, keep small, regular acts such as prayer and dhikr.
If low mood lasts, seek help as well as spiritual support.

Tip: Decide your "minimum" on low days, for example the five prayers plus a short dhikr. Keeping that minimum protects you until your energy returns.