Hello there @abumaryam :)
Before anything, let me just say that I love, love, love the description of yourself you share on your blog "An ardent reader and a curious listener" :D Gosh, someone who is keen to read and listen, in my opinion, is halfway there! With 'there' being 'high levels of subjective well-being'.
I am so sorry for your loss and the pain you went through because of it @abumaryam. I truly understand it. But, here is the thing, do you really think it is realistic "to be like before" after all you went through? After all the things you learnt and saw because of the journey you made? No, it isn't!
I disagree with that sort of goal. Not only is it impossible, but it is also backwards. Why not, instead of looking at how you were before, envision that @abumaryam you would like to be tomorrow, next week, month, year, decade. Now, that is an achievable destination!
One that you can reach with the lessons you learnt from losing your mum. However, feeling guilty about what you didn't do when she was around is just going to slow your journey there! But, avoiding repeating those actions again with other loved members of your family will just get you there quicker.
Would you care yo tell me then, the person you wish to become tomorrow and focus on that? After all, don't forget what we discussed here in this very post. If you focus on who you were before, how will you be a better person in the future?
All the best to you :)