What Could Be Causing My Oral Thrush, Gum Pain, Recurring Lesions, Mouth Bruising, And Constant Headaches?

I have oral thrush, and I have this gum bleed not bleeding per day but it’s red and painful And I have lesions that go and come back also there is bruise at corners of my mouth and I’ve had constant headaches for about a month now It goes when I take painkillers but comes back when I don’t take them What could be wrong