Assalamualaikum, woke up with sore throat and blood comes when spitting. I tried to expel as much as I can but it hurt so Imight have swallowed some intentionally, I decided to gargle a bit of water to soften it. If something went through is my fasting valid?

So i might have swallowed some intentionally, this sounds to me like waswas akhi. Go to a doctor may Allah reward you. As for gargling, it does not break your wudhu as long as you are careful and don't swallow. Same thing applies to the blood as it is difficult to stay away from, so if you have swallowed by mistake, it doesn't break your fast.