whenever i try to get anyone to follow me, they would always reply me with "looks like you've got someone following you"
Problem: no one is following me
i think i attribute this to the companions quest, purity, given out by vilkas
he would start by saying that we would need to venture to blabla to cure him
however, as soon as i leave the house, the quest would somehow be completed and vilkas would just walk away, this results in me going back to him and the same thing happens AGAIN
now i have a total of 3 purity quest in my quest log all under the completed section but in actuality uncompleted

the real issue is how do i get companions to follow me again?

Might be a stupid question but you dont have a companion on "wait" somewhere do you?

Same thing happened to me but turns out i told Lydia to wait outside of riften while i was stealing something. Couple of days later, there she was, obeying my orders.. Best housecarl ever!
Good luck!

Bethesda should make them auto-reset if you fast travel while they are on wait.

Most commony caused byhaving your housecarl wait in the house to keep her out of your room and away from your sweetrolls.