feeling happy

She is feeling happy because today is John's birthday.  

Yes, that's fine. What is it about John's brithday that makes her happy?

It seems when people are learning English, there are a number of verbs they are first taught cannot take the progressive, the -ing form.

Then, when their English becomes more advanced, they learn that these verb (liking, loving, feeling, being) CAN take the -ing form when you want to emphasize that the situation is CURRENT and likely to change.

You are BEING a jerk is different from You ARE a jerk becuase I mean that only at this very moment are you are jerk. You are not usually.

I am LOVING this salmon dish - Usually I don't like salmon, but this is great. Right now, I am really enjoying it.

It's the same with She is feeling happy. At this very moment, that's how she is. Maybe she's been a bit sad lately, but knowing that there will be friends and cake at John's house later is making her feel a bit happier right now.

That was probably my worst example. I just wanted to emphasize the "wow, I love it" aspect of the moment.

Maybe it would be better to say something like "The meal is okay. I mean, the meat is good, and the veggies are fine, but boy oh boy, am I LOVING these garlic mashed potatos. Those are just terrific. The best part of the dish by far."

Hi New2grammar,

The verbs GG pointed out (Like , love etc…) don’t take on the “ING” for when used in a casual environment. Usually, when  people say “ I love Paris”, they mean they are deeply fond of the City and everything about it but they may not be there at the moment. If say ^{“I am loving every mintute in Paris”,} I am emphasizing how I am feeling as I speak.

I am not sure if the Mc Donald slogan is the same in your part of the world but in the US, “I am loving it!” becomes the advertising slogan for McDonalds almost everybody knows.