I appreciate your honesty, I can relate b/c I’ve been there at points in my life too, including the weed. three things helped me kick/reduce all those habits:
stop expecting perfection from myself by giving myself lots of internal validation every day & replacing self-loathing thoughts with gratitude
break apart overwhelming tasks into stupidly small tasks like "write the first word of the first paragraph, then the next word, etc"
be my own parent & stop using weed, other substances and addictions like videogames to distract from the present by deciding to take short breaks (e.g. 1 day/1 week/1 month) & telling myself I’ll keep going if I feel good after
I can recommend a book called Don’t Believe Everything You Think, it’s a short & easy read that reminds you why it’s good to be in the present & that all the answers you need are already within you if you’re honest enough with yourself to ask & answer those questions. good luck!