Is it normal to be so angry at my sister/her boyfriend?

I'm a 20 year old college student living at home. My 21 year old sister also lives at home. We used to be great friends, up until a about a year ago when she got a boyfriend. Now, she's practically with him 24/7. They work together, and pretty much whenever she's not working, she's still with him. She comes home every single morning between 3 and 4 and wakes me up as well as my parents (we have a dog that barks every time). It really annoys me because she keeps promising to do things with me, like go shopping or out to lunch, but at the last minute she always cancels and says she's going out with her boyfriend. She ignores me most of the time, unless she needs a favor from me. Also, her boyfriend is a total bum. He's 28 and only works part time at McDonald's. He always drives my sister's car or makes her drive him around (if he's drunk) because he has no insurance and his car isn't registered. They go out to dinner every night but my sister always has to pay. He likes to go to the bar and go to the casino and gamble a lot. He calls my sister names and makes her cry and makes her feel guilty if she does anything with anyone else. My sister always takes clothes in a backpack and changes into really slutty outfits at his house. She never used to dress that way. He's her first boyfriend, but she started sleeping with him after only a few weeks. I think he's totally taking advantage of her. I feel like she's using my parents too because she drives my dad's car and stays in my parents' house but does nothing in the way of chores or spending any time with the family. Not even on Mother's Day or Father's day. Not even a card or anything. I can tell my parents are really hurt by it but they don't know what to do. She really doesn't care about anyone except him, and she admits it. I don't know if I'm more mad at her or the boyfriend, but I hate it. It makes me really angry. Is this normal that I'm angry?