Assalamu alaikum ustadh I broke an oath where i said i wouldnt do something, it was at a time where i was psychologicaly unstable and suffered from psychosis. Im not 100% sure if i was clear in mind at that time and already healed. What should i do, do i have to feed 10 or fast?

If your mind was present and you were stable, and knew what you were saying, the oath stands and breaking it requires the kaffārah: feeding ten poor people or clothing them, and fasting three days is only for one who cannot do that. If your mind was gone at the time and you were not stable, the oath does not form and nothing is owed in sha'a Allah. Keep in mind nothing we say here is to be taken without referring back to your doctors as they know what might affect you positively or negatively.