There is a difference in the usage of feelings for and feelings about.For eg.A person says “I have developed feelings for her” Then here he means that he is in love with her.You can also take it as that he has a soft corner for her,she is very special to him.
Feelings about can be used for positive and negative feelings.For eg Latha tells Sudha “I have a bad feeling about Shreya.Here she means that she does not have a good opinion about shreya.Feelings about can also be used in a positive way.
Ram tells his friend ” What are your feelings about Ravi? He seems to be a gem of a person.Feelings for is always positive feelings whereas feelings about could be positive or negative feelings.