Why would detoxing make me feel so ill?

I overindulged over the christmas period so decided to go on a healthy eating plan this week. This is my third day and already since I've been on it, it has made me feel very ill. This is roughly what I have eaten over the last two days:
Mon:
Porridge, semi skimmed milk, dried fruit
Jacket potato, tuna (no butter or mayo), a banana
(I slipped a bit here and tried one of my child's homemade cupcakes)
Rice and curry made with small amount of paste, tinned tomatoes, peppers, onions, quorn peices, tinned potatoes.
Cherries.
Pear

Tue:
Porridge, semi skimmed milk, dried fruit.
Pear
Sushi, Raw Carrots, Pure fruit smoothie.
Banana
2 x sesame ryvitas
Strawberries
Same Curry and Rice

...I have also been drinking plenty of water but havn't yet managed to wean myself off the coffee (I have 3-4 cups of this a day).

I felt fine when I wasn't detoxing but now I have stomach cramps, mild diarreah, gas, headaches, I'm tired and have no energy and I'm starting to get a sore throat too.

Any idea what's going on. Is it a coincidence that I'm feeling ill or is it my change of diet. If so will it go away or is there something I should change?
Can I just say in response to some comments that i am not trying to lose weight I am trying to be healthy. This isn't a detox plan. Maybe I've used the wrong wording. I'm just cutting out sugars, salts, and wheat and cutting down on dairy which I know your body has no need for any of these.
Please look at my meal plan, it is not at all dangerous and I am not starving myself

: http://alcoholdrugstreatment.info/why-would-detoxing-make-me-feel-so-ill