Heat exhaustion or other problems?

I'm a very active person who loves nothing more than to keep fit, my life is revolving around it at the minute, not in an obsessive way, and so I make an effort to eat the right foods and do the right things. But the past week I think I've either failed myself somewhere, or the heat of Summer has hit me more than usual.

I've ruled out dehydration due to me drinking water all day long, I've ruled out the possibility that I don't eat enough because I have four to five small meals each day, I've ruled out me being worn down because I don't have much stress in my life at the minute, I haven't ruled out me not eating enough vegetables, which is now probably taking its toll on my body - I have, however, done my best to rectify this problem by eating vegetables on a daily basis now, no matter how much I dislike them.

I've been feeling pretty lethargic all week and was in a race against time to be fit for football yesterday afternoon - and the result of that race came to a miserable conclusion half way through the match.

I managed to make it to the end, but not without getting cold chills in 32C heat, nearly passing out toward the end and almost collapsing to the ground in one last push at goal - to sum up the feeling of my body after the match? Exhausted. I ate all the right things before the match, drank plenty of water before, during and after and did the required amount of warm up exercises before the game, yet come the end I was ready to dig my own grave - although I doubt I could have even managed that.

I've felt alright today but my physical activity has been kept to a minimum, although I have just finished my routined weight-lifting work out. I think if things don't get better with me in the next couple of days, I'll be forced to make a visit to the doctor for a blood test or something. I've spent much of the day writing my next article for a certain website as well as filling in an application form for an IT Technician post at a local Secondary & Science school - something which took nearly four hours to complete - sign of desperation there?

In other news, I'm quite happy and relieved that Space Shuttle Discovery has succesfully completed its mission of dropping off a Germany astronaut and a few other supplies for the ISS today. It landed back at Kennedy Space Centre, Florida, at 13:14 BST.