i was sick = j'etais malade

there were sick = ils etaient malades

were (pluriel) was (singulier)

Quand tu as les pronoms personnels Je, Il, Elle et pronom neutre, tu dois utiliser was. C'est en faite l'imparfait. Donc I was, He was, She was, It was. Ce sont les personnes du singulier

Pour les autres ( tu, vous, nous, ils, elles) tu utilises were. Donc you were, we were, they were. 

I was born in August 

You were born in June