Been taking care of my body and feel more angry, heartless, and aggressive. Why might this be?

Before working out an hour a day doing high intensity aerobic and going on a super healthy meal plan I was a cigarette smoker and ate like crap and did not workout, but felt less like I mentioned in the question. It has been a month sense I smoked a cigarette and started to workout, just started to eat super healthy a couple of days ago after getting money to buy my own food, before that I was making do with what I had with who I am living with. Could it be my diet. It's a lower calorie 5 meal a day plan. Consists of walnuts, almonds, oats, milk, lentils, olive oil, garlic, cilantro, white bread, steak/chicken, vegetables, fruit.. personally I was thinking the lifestyle change is changing the chemistry in my body, but my habits are still pretty much the same given I am poor so my body doesn't know what to do and it's all coming out as anger or hatred...