Add a Do While Activity before the first If Activity and type the condition that must be satisfied in the Condition section. Then move the rest of the activities inside the Body section. To be easier you can even collapse the first If activity before move it.
Following your graphic, I did not see any new assign for your variables SITE and WO. Also I see an Break activity, I suppose that you are using a For Each activity, in that case you can add an if activity next to your nested if checking if your WO and SITE variables are empty.
I have tried a different method using If else activity for the “WO” i which i left the THEN part empty with no activity so that i can skip the process and proceed to scan the next “SITE”.