Here's my best answer for this shit.
Meaning, purpose, and value are not things that exist outside of consciousness. Saying that life is meaningless is just as ridiculous as saying life is painless. meaning can not be struck with a hammer or placed on a scale and measured, feelings of meaning, purpose, and value are our reactions to things.
It's like how if you put your hand in a bucket of hot water and felt pain, there's no pain in the water, the pain is your reaction to the water.
You say that you feel like nothing matters, well that's really up to you. Like I described there's no scale to measure how much something matters. YOU decide how much things matter. YOU decide what has meaning, purpose, value, etc.
The easiest way to get past these feeling is to realize that they are counter-productive to success. Are there things that you would like to get done with your very short life? Or are you content to LDAR?
If you want to get things done these thoughts are intrusive and distracting at best.