Am I a bad friend?

Hi there, so uH.. I think I’m a bad friend.. I hope this doesn’t sound too childish or anything, but I genuinely think so because I often ignore people... not because I hate them or anything, I just.. don’t have the energy in me to reply? I’m often relied on by my friends to vent to and I’m perfectly ok with it. But sometimes, my brain shuts down and I don’t know how to respond and I feel tired. I still care for them, but it feels like my brain ran out of fuel mid conversation.. I have a friend I consider closer than family and she’s been having a rough time lately but I’ve been dodging her calls.. I do want to be there for her but I never know what to say, thus me not accepting her calls.. I feel bad and I don’t know what to do.. in the first place, I can’t really display “happiness”, yes I can smile, but it feels weird, I feel like I’m just copying what others do. I laugh when I hear others laugh, but I don’t know what the joke is. I can’t cry normally, only when I’m under distress or being pressured, if that makes sense.. I didn’t even feel sad when I broke up with my girlfriend even though I felt such joy in the beginning. Was it puppy love?? I don’t understand.. how can I understand emotions?? I hope that didn’t sound too chunni but I need help, I don’t understand myself.. should I admit it truthfully to my friend or should I keep this to myself? I don’t want to put her under more stress.. I can’t even put this on my socials.. aghhh what do I do??? ╥﹏╥