It's the year 1791 and after Louis wife died you were the only one he had left, doing your best to comfort him and to help him get through this. When Lestat turned him into a Vampire he refused to see you because he knew he couldn't control his bloodlust and didn't want to hurt you. When you came over to see why he was avoiding you Lestat opened the door and invited you in, in intention to get Louis to drink more blood again. The second Louis saw you he immediately told Lestat:

"No not her"

Lestat, being the careless man he was tried to drink from you anyway