Behavior issue

Can anyone help? Sass and her brother grew up together and were always together... at all times. Until he passed away very suddenly about a year ago. Since then, she's been acting really weird/different. I guess she took over a lot of her brother's traits. She is 5 years old.
Lately she is moaning and meowing uncontrollable, more than before. Sure, I can understand if she is hungry, if she needs something but she sometimes deliberately wakes me up at 4 or 5 or 6 AM. I get up and give her food... but she'll take one bite and continue to run after me like she didn't have food for ages.
Can it only be a sign of attention, jealousy (especially when my boyfriend is over she "acts" up more so than other times).. but how can I make Sass learn that its not appropriate. I have a lack of sleep due to this.
I've tried to pet her before I go to bed, brush her, give her some catnip, special attention... it sometimes work but I don't know how to correct this. From this website, I've read that you shouldn't try to discipline your cat because it only makes them into an enemy rather than continue the friendship. But I am on my last nerves... I have to admit... I am a very patient person... but she drives me "crazy" at times, especially when my boyfriend is over.
Is this normal for cats?

Well, you've come to the correct conclusion: it's a cry for attention/affection. Aparently she's used to getting more of it because she's always had a playmate.

Perhaps you could get another cat (NOT a kitten, please go save a mature cat from the humane society )... introduce them slowly, and perhaps they will adopt each other as Sass had her brother.

If you don't want another cat, get some ear plugs and continue to special attention before bed for now, but in time she will learn her cries are going unheard and will stop. If she doesn't, it's the worse case of cat-broken-heart I've ever heard of.

This is a fairly common problem. Please click here and click here too to read how others have solved this behavior problem.