Does divorce occur in the two aforementioned situations: the first being when the wife is pregnant, and the second being during extreme anger and the wife's accusation of infidelity?

The divorce of an angry person is valid unless his anger deprives him of his sanity, making him unaware of what he is saying. If he is conscious of what he is saying, then his divorce is valid. The divorce of a pregnant woman is valid whether he knows of her pregnancy or not. If you were conscious of what you were saying, then your divorce has occurred twice, and you can take her back now.