Ego has nothing to do with Astaghfar. Take a look at "Sufees" who do so much Dhik'r and have ego the size of mountain. Ego is about training
Train yourself to:
Do this again and again and keep doing it until your last breath. Sometimes you will loose and sometime you will win but gradually you will get better.
The one in bold is most important and most obvious parameter. Begin to observe people in your life and you will see in no time that many people make excuses, argue, debate, defame, slander others BECAUSE it is easier to to do so then to admit their error. This is the sign of Shaytaan, when he made a mistake he did not admit and justified his behavior and his "ego" got him where Shaytaan is today.
Test this theory if you want and it is usually always right.
We are all on a journey and until our last breath, improvements will be needed and it will never end except the "Sufees" because they have a ticket to paradise just on account of being Bay't to someone or being part of some silsilsa.
Normal and ordinary Muslims will make mistakes, repent, stumble and tumble.
Remember, you are human and you will make mistakes and keep on making mistakes. You will miss reading Qur'aan, you may miss your Salah and you will also commit sins...C'est la vie
This cannot be undone and I am sure it will be greatly appreciated.