"There is a time in the lives of most writers when they are vulnerable, when the vivid dreams and ambitions of childhood seem to pale in the harsh sunlight of what we call the real world. In short, there's a time when things can go either way."
Stephen King
King said that his wife, Tabatha, kept him going when he doubted himself. I hope you are lucky enough to have somebody to do the same for you.
I've been lucky that way. A personal note from Rod Serling, to whom I'd written a fan letter when he was in the hospital in LA, fanned my childhood ambitions. Later, my best friend Bob and a wonderful eccentric named Rose also kept me going when I was trying to break into the screenwriting world in Hollywood with no contacts and a limited nest egg.
Along the way, a few more people kept me excited about writing, including the late Stan Margulies, producer of Roots, and Stephen Cannell, who I interviewed several times and who was generous with his time and advice. So were Sterling Silliphant and Alvin Sargent (the latter still active as a screenwriter as he approaches his 88th birthday).
Having the chance to work with one of the Mony Python crew, Graham Chapman, was also a dream come true, even if the project we worked on was doomed. And now I have the support of my partner, Sheridan (and Rose and Bob are still hanging in with me, too).
If you don't have anybody like that, consider this a nudge from me, a grateful recipient of several such nudges, to believe in yourself and keep writing.