Many people see the attempt of writing a novel or novella as an impossibility.
However, if you have penned a long short story – say, 5,000 words long – then you can always lengthen that story and turn it into a novella.
A count of 5,000 words is one-sixth (1/6) of the way through completing a 30,000-word novella.
If you think about it, some of your shorts will be justified if you lengthen them.
Time – and a good eye and ear - can send along to you events that you can use to thread into the short story to turn it into a novella.
Keep looking and keep listening.
(Oh, do you listen?)
WHOLE LIFE – OR IN A YEAR
Some people prefer to write one novel in their whole life.
(Some plan to, but never do it)
If you really, and truly, want to become a writer, you should try to at least pen something lengthy once every year – a long short story, a novelette, novella or novel.
You might not complete all of them but at least you are pushing yourself to put “something heavy” out each year.
When you go “lucky” on one of those “heavy” projects (as when one is published), then you can go back to the others and nicely tidy them up.
So, in a lifetime, you can have more than one big work.
That, I think, should be the goal.