Salam aleykum I swallowed blood from accidental nosebleed than remembered it might break the fast , is my fast valid and whats the ruling swallowing mucus or what comes from the chest ? Baraka Allahu Feek

Valid, don't fall into waswas. Mucus is fine. If something comes out from your chest or stomach spit it out. If you swallow them by mistake or due to hardship, then there is nothing on you. Again do not fall into waswas.