May Allah raise your rank and keep you healthy. Ameen.
Lately, I have had some fights with some sisters and my Imaan is at an all time low. I have the feeling my heart is hard. I try to attain some more knowledge and do more actions and worships. The feeling of my heart does not leave. I start attacking people who have nothing to do with it but approach me on a bad way. Normally, I would only act as if nothing is wrong. It has become difficult now.
I do not know what to do to make me strong again. Is there any advice? May Allah reward you with goodness.
First and foremost, I ask Allah to cure your heart from any hardness or cruelty and to guide you to be amongst the people of gentleness (rifq). You need to learn about the name of Allah Ar-Rafeeq (الرفيق).
What there is in your heart indicates that you are not on the right path. I have explained before that this tightness in the heart is the result of not following the way of Allah. Although you think that you are fighting for the sake of Allah, got angry and told bad words for His sake, this is not the way Allah loves you to act. Allah wants us to be gentle (رفق), merciful and kind to each other.
The best thing to do now is firstly to ask Allah to forgive you. You can say:
لا اله الا انت سبحانك إني كنت من الظالمين
Laa ilaha illa Anta [none has the right to be worshipped but You (O Allah)], Glorified (and Exalted) are You [above all that (evil) they associate with You]. Truly, I have been of the wrong-doers.
Secondly, you should apologize to the sisters and tell them nice words. It will make this hardness in your heart and these bad feelings disappear. The way of good Muslims is to make the first step, be humble with these sisters and ask them to give you advice in order to change yourself.
If you want to be gentle, you need to put this into practice. Do not let your nafs (yourself) to do whatever it wants. You need to force yourself and take control over yourself, over your temperament and over your tongue. This is what Allah likes. It is very important to take the intention to purify your nafs and your heart for Allah’s sake while you are having this fight. This is what pleases Allah.