Thanks so much, your replies have been very helpful to me. It is sad to know my website crashed and went offline yesterday after /dev/sdb1 reached 100% storage with no space left, i had to stop and restore my Vm-instance with an old snapshot in order to get my website back online.
After this, the /dev/sdb1 was back to 48% but this morning it is now at 62% after using the commands you shared with me to check it out. It think something is eating up the storage space in the Mysql folder.
After runing the commad this is what i see
banjicom4real@wordpress-1-vm:~$ cd /opt/bitnami
banjicom4real@wordpress-1-vm:/opt/bitnami$ sudo du -h -d 1
I can see a folder with no name taking up 6.6GB of space..........