(I am assuming you mean Marianne's almost "dying of a broken heart", etc.) are very different from Lizzy's reaction to Charlotte in P&P. Marianne believed feelings trumped everything else, including life and health. Lizzy, on the other hand, sees her friend marrying a man no one could respect. The match is not comparable to, say, Marianne's marrying Col. Brandon without being in love with him. There was no possibility of Charlotte falling in love through the years, no possibility of her even liking her husband.

Lizzy has grown up with a father who could not respect or like his wife. The relationship between her parents causes constant friction in the house. Her sisters' improper behavior is another result of the mismatch. She probably imagines the sensible Charlotte will have as miserable a life as Mr. Bennet does.

I think it was very natural for Lizzy to react with shock and disbelief, and to be very hard on Charlotte. Lizzy realizes she doesn't have as much in common with her best friend as she always thought. She didn't "drop" Charlotte, as some have said, but I think it very understandable that she no longer seeks Charlotte out as a confidant, especially in matters of the heart. She can't expect Charlotte to really sympathize with her, or to do otherwise than advise her to act in a mercenary manner towards the various men in her life.