23 yo with depression/anxiety/low self esteem

I am a 23 year old guy, who has been suffering from depression and anxiety for the past year or so. I generally follow a very healthy life style trying to avoid junk food/fat stuff as much as I can.

It started out with panic attacks that then became a lot more frequent, up to two/three a day. This sort of came to and end at some stage but I still suffer from anxiety. I'd been seeing a
psychologist which helped for a while, I was under prozac too. Then I stopped it not to mess up my brain and also because I was feeling better but it seems to be coming back.

I feel restless, I am afraid of feeling bad, of dying, of being left alone, I get headaches and think my head will explode because I can't stop it. It's like I have a million things going back and forth
and it would not stop. When I wake up in the morning I feel broke though when it's time for bed I never feel sleepy.
I live abroad so whenever I fly back home.. this is another big problem, I can't fly anymore. I mean, I do, but I feel horrible and can't wait for it to be back on the ground. It also happen in general
when I need to travel from one place to another which requires long preparation, both mental and material.

When moments like these come my heartbeat fastens and I sweat easily, I get very irritated and feel worse if I'm in a crowded place with a high room temperature.

(On another note, I have also noticed that the quantity of my sperm has diminished to almost half of what it used to be. Can this be linked to the depression?
I am very skinny and always had low self esteem for this, is there any way I can put on more weight, develop my bones and muscles in a natural way?)

I would ask for your help as this situation has been putting me down a lot and if you need any more information just let me know.

Thanks a lot,
A.