I don't know what a DL sport means, but, vision that appears red is suggestive for a vision condition known as "red-out" linked to body acceleration.
Actually, this happens when the body gets negative acceleration stress with throbbing pains throughout the head and temporary loss of vision or all objects appear red.

Thanks for the reply, but I think that condition is related with going at like 5gs which I am definitely not going. My sport doesn't entail going much faster than a medium speed runner.
DI means division 1, im just trying to get across that its an extremely physically demanding practice.
any other ideas?

Your symptoms sounds like ones of heat illness, that can be manifested in mild, moderate, and severe form.
Gastrointestinal complaints in sport are common, particularly in endurance exercise.
The blood flow to the abdominal organs can be reduced up to 80%, leading to lack of blood to GI tract, resulting in gastrointestinal symptoms (nausea and vomiting occurring during or soon after exercise due to gut lack of blood).
Dizziness following exercise is not uncommon, especially if the athlete suddenly stops exercise when exercising upright. This causes blood to pool in the lower limbs and the cardiac output suddenly drops (postural hypotension).
You are probably, experiencing exertional headache, that is benign and occurs following relatively intense exertion, commonly weight lifting and running.
The onset of headache is usually acute and severe but this lasts for only a short time (seconds or minutes) and is followed by a dull ache which may last for many hours.

You may ask for complete check up, especially, your heart and circulatory system, and talk about what is appropriate hydration.