Hi ! My name is Amie, I am almost 70. Holy Moly, it's the first time I have admitted that to anyone ! And while I have experienced panic attacks, I have never experienced what you are talking about. I have experienced odd symptoms - usually during times of immense stress. Stress can do wierd things to your body - from chest pains to hives (going on 11 months now).
I haven't been able to cry since my Grandma died. I am guessing you were close to your dad as I was to my Grandma. I am no doctor, but I also think that there is a reason for the inability to cry. I believe it is our bodies way of protecting itself. I truly believe that undergoing these traumatic times in our lives - our brain and body protects itself.
I have only seen a therapist for a short time, but I also believe in my heart, that when we are ready to face and come to terms with these losses, we will be able to cry again (maybe). But I am not sure at what it will cost us emotionally.
This might sound a little crazy, but I talk to my Grandma all the time. Both out loud and in my head. It brings me comfort to do that.
I wish you well with what's going on in your life. Cut yourself a little slack and be kind to yourself. Worrying will not bring any comfort. I have been telling family that I finally figured out that all my issues are emotion based - IBS, migraines, chronic pain, hives. Now it's time to learn how to cope with them. Whether that means making changes in my life or delving into root causes and heal myself or just letting myself just go bat-shit crazy for awhile.
Good Luck ! I would love to keep in touch, but I am new to this website and have no idea how to do that !