Face it. You are overwhelmed.
I know this because I have been overwhelmed.
It is being overwhelmed, suffering the overwhelmingness of it all, that leads us to question why? Why exist? Why act? WTF?
Now let's be clear up front. If you have a plan and feel like you are ready, or getting anywhere close-to-ready to harm yourself (or someone else) - stop. It is that simple. Just stop.
Get emergency help. Just do it. It will be worth it in the long run. In other words, if you are thinking of ending it all go here now.
The despair is in believing there is no hope for a brighter tomorrow. Of course, for those who have made it through the loss of hope, we know that there is something wonderful on the other side. It is getting past the suffering, the despair, that is the hard part. (Until is becomes easier with practice.)
Personally, I have re-learned multiple times in my nearly six decades on this planet that working with counselors and clinicians to regulate one's mood can make all the difference! So if you are a miserable SOB, and you don't yet have a mental health professional involved - it is time. Now. Do it.
The problem is that if your perspective is skewed by a lack of awareness that you and your feelings/mood are distinct from one another - you can end up fucked. Medicines and therapies (e.g., CBT, DBT, etc.) on a daily, weekly, or other schedule can immediately help those suffering the most. If you are suffering more than others, do you have a professional plan of how you are going to manage the suffering? If not, you are just feeding your pain. Like a pig in shit, you are loving the pain. Or getting something from it. Or something fucked up. So let's get back to the basics.
You are NOT your feelings. They are just one part of you. You, in total, are the sum of your parts. This includes your feelings, including the overwhelming ones, the voices in your head, the organs in your body, and the uncountable number of organisms that make up your biome.