Website is very slow

Hello,

Recently my website is extremely slow. We did not change anything on the site but it looks the last automatic update of wordpress made the whole website very slow. I can see the website is using 80% of the CPU. could you please help?

User Domain % CPU % MEM MySQL Processes
estarreg estarregistry.com 79.96 13.48 4.1
mysql 2.66 2.44 0.0
root 1.77 3.06 2.0
cpanelsolr 0.07 5.48 0.0
nobody 0.03 1.23 0.0
dovecot 0.01 0.00 0.0
named 0.00 0.30 0.0
mailnull 0.00 0.10 0.0
nginx 0.00 0.10 0.0
dovenull 0.00 0.09 0.0
dbus 0.00 0.00 0.0
mailman 0.00 0.00 0.0
nscd 0.00 0.00 0.0
sshd 0.00 0.00 0.0