May Allah forgive your mother and grant her a buland darjat in jannah and grant you sabar and strength during this trying time; Amin.
There are indeed many worthless things and pursuits in this world. But there is also much beauty and good in this world, too. Much of what makes life beautiful and worth living for us and for others come from the good and kind acts that we do...things that reflect our love or care and humanity for those that we know and don't know. With that said, your mother will benefit from acts of sadaqah jariyah that you do on her behalf, which will also ease the burden of other living creatures (people and animals). It's one of the best gifts to give our loved ones; to do sadaqah on their behalf and especially sadaqah jaariyah which is continuous.
It might help to remind yourself of how your mom would want you to carry on. For example, no parent wants to see their child (no matter how old) in pain or grief and especially to become consumed by it. Try to remember the sayings or words of courage and strength and motivation that your mom would often say to you.....try to remember the things that she would both do herself and advise you to do during difficult times....such as praying or doing dhikr/tasbeeh...etc. Maintain good relationships/ties with the people that your mother loved such as your siblings, your aunts and uncles, etc) and her friends as a way of honoring her and their company can be a means of solace of comfort as well.
Dhikr is also very helpful. It's like a balm for the heart. The hardest part is getting started. But once you you get started, in a matter of minutes...you will get into the rhythm of doing dhikr. Your tongue will be occupied by the words and if you can also get your mind to focus on the meaning of the words......then for some time your mind/heart will be diverted from the thoughts that are troubling you. One of the best dhikr you can do is salawat or durood. You can recite Durood-e-Ibrahim which we recite in namaz or even a shorter durood such as ....Allahumma salli aala Muhammad wa aala aale Muhamamd...or...even shorter....salallallahu alayhi wa aalihi wa sallim. Durood is the only dhikr that is guaranteed acceptance and it has a cooling effect on the heart and mind when one feels troubled. You can even recite it upon water and drink it (throughout the day) and after reciting you can make dua to Allah to gift the recitation as isaal-e-sawaab to your mother.
You take it one day at a time. If that's too much, you take it one hour at a time or a few minutes at a time and try to stay within the present moment because thinking about the future can cause more anxiety because we do not know what the future holds. Lean on your immediate family and relatives for emotional support.
When you look at what is happening in the world around us, many of the predictions that our Prophet SAWS about the end times have come true. Our loved ones that have left this duniya are in another realm and in another form ..one where they do not face the trials of this world and where they are united by former loved ones that passed before them. I once saw a video in which a scholar said that after we pass away...our souls are united with our loved ones that passed away before us and the souls converse with each other about, "Have you seen so n' so?" I know it's easier said than done, but we have to cling this hopeful belief that leaving this world is not a complete termination and that it contains a reunion. This world is too complicated in its design to be purposeless.
You're going to be okay, Tubelight. You're going to get through this. You carry your mom's blood in your veins...you carry her voice in your ears and your mind...you carry her teachings, her words of wisdom, all her lessons that she taught you within your heart and within your deeds/actions ...every single day as you put one foot in front of the other and push forward in life (because you KNOW that SHE would want you to do that). According to hadith, the actions of one has passed away cease except for 3 things: 1) ongoing charity/sadaqah...2) beneficial knowledge.....3) and the righteous child who prays for them. So...be that righteous child....and put into action all the beneficial knowledge and advice and teachings your mother gave you and teach them to others...and this will benefit her rooh and it will be a means of honoring her and keeping her within you at all times every day.
May Allah ease your hardship and give you and your family patience and strength up on strength. Amin.