Extremely slow Nginx download over ssl

i have a 512 Mb droplet and ngnix 1.9.5 , Nginx is as slow as HELL when accessed with HTTPS , it wasn’t like that sometime ago , i’ve applied my current configuration to another VPS i have and it worked smoothly i tried to reboot the droplet , but no still no luck . i don’t know exactly what’s the problem , i’m using the default Nginx SSL configuration and tried a few more all didn’t work , i also checked the droplet resources usage it’s okay , i’m trying to access it with curl , browsers anything it’s so slow . however if i accessed the same url with HTTP it works without a doubt .

Here’s my configs

    server {
server_name admin.ex.com ;
listen 80 ;
listen [::]:80 ;
##SSL
#listen 443 ssl ;
  listen               *:443 ssl http2 ;
  listen               [::]:443 ssl http2 ;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

#ssl_ciphers "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH:ECDHE-RSA-AES128-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA128:DHE-RSA-AES128-GCM-SHA384$
ssl_ciphers   EECDH+CHACHA20:EECDH+CHACHA20-draft:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;
ssl_prefer_server_ciphers on;
ssl_dhparam /etc/nginx/ssl/dhparam.pem;
ssl_session_timeout 10m;
ssl_session_cache   shared:SSL:10m;
ssl_certificate /etc/nginx/ssl/admin.crt;
ssl_certificate_key /etc/nginx/ssl/admin.key;

root /var/www/admin/public/;
index index.php index.html index.htm;
access_log /var/www/admin/admin.log;
auth_basic "Top Secret";
auth_basic_user_file /var/www/admin/.htpasswd;


        location / {
try_files $uri $uri/ =404;
allow 192.168.1.1;
#deny all;

location ~ \.php$ {
fastcgi_pass unix:/var/run/php/php7.0-fpm.admin.sock;
fastcgi_intercept_errors on;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root/$fastcgi_script_name;
}

}


}

Again , i’ve tried many many SSL configuration including the Nginx default ones . currently i’ve 4 Vhosts with estimated 10 visitors per day and CPU usage never exceeded 12%