Idioms about Feeling:
General Feelings:
* To be on cloud nine: To be extremely happy.
* To be over the moon: To be very happy.
* To be down in the dumps: To be sad and depressed.
* To be in a black mood: To be in a bad mood.
* To be feeling under the weather: To be feeling unwell or slightly ill.
* To have butterflies in your stomach: To feel nervous or excited.
* To be a bundle of nerves: To be very nervous.
* To be on edge: To be anxious or worried.
* To feel blue: To feel sad.
* To have a gut feeling: To have an instinctive feeling about something.
* To be in a good mood: To be happy and cheerful.
* To be in a bad mood: To be unhappy and irritable.
* To be in high spirits: To be cheerful and happy.
Specific Feelings:
* To be green with envy: To be very jealous.
* To be red with anger: To be very angry.
* To be cold as ice: To be unemotional or indifferent.
* To be scared out of your wits: To be extremely frightened.
* To be sick to your stomach: To be disgusted or upset.
* To feel your heart sink: To feel disappointed or discouraged.
* To be bursting with pride: To be very proud.
* To be in a daze: To be confused or disoriented.
* To be on pins and needles: To be anxiously awaiting something.
Figurative Idioms:
* To wear your heart on your sleeve: To be open and honest about your feelings.
* To have a heart of gold: To be kind and generous.
* To break someone's heart: To cause someone great emotional pain.
* To follow your heart: To do what you feel is right.
* To have a change of heart: To change your mind about something.
These are just a few examples, and there are many more idioms related to feeling. The best way to learn them is to read and listen to a lot of English.