Sooo I want to keep this kinda short but I am looking for an answer. 
I used to workout and weight train at least 4-5 a week no problems I was very very fit done this for 4 years

I have taken a year break and Iv noticed now after exercise (HIT or weights) about an hour after the workout I have really really bad anxiety and panic attacks. 

Sometimes it dosent happen on the same night it will happen in the morning depending on when I workout and the anxiety is just sooo bad , to calm myself down I take histamine and I calm down straight away. 

This is really bothering me especially that I used to love training before. 
However when I walk for 20 mins I am ok it’s when I train harder. 

Please help someone