Why is eye all of a sudden red with little white spot on like iris I think?

Burst blood vessel. I think you are describing a "subconjunctival hemorrhage" which is when a small blood vessel bursts under cornea, or white part if the eye. These can be caused by trauma, a cough or sneeze, straining to have a bm, or by surgery. They are benign and should by entirely without symptoms, i.E painless, no discharge or problems with vision. If you have any of those, see your doctor as soon as possible.
Likely corneal ulcer. This is a potentially serious infection of the cornea, the clear front covering of the eye. Much more common in contact lens wearers. Take your contact lenses out immediately and see an ophthalmologist within 24 hours.
Corneal infiltrate. Its probably on your cornea, not the iris. Typically these are called ulcers but it can be either infectious or immunological or a scar. Since you don't seem to be complaining of severe pain most likely its from blepharitis, an immunological reaction from staph toxins or contact lenses, or its a scar. Still need to see your eye doctor.
Cornea ulcer. It can be a cornea ulcer which is an infection that needs to be treated urgently. Stop wearing your contact lenses and see your ophthalmologist.
White spot on eye. The conjunctiva commonly has an area next to the iris at the 3 and 0 o'clock positions which has little vasculature. If there is bleeding under the conjunctiva it commonly spreads over everything except this small area which then is highlighted with the surrounding red and looks like a white bump. This is an optical effect and not pathology.