LEARN TO SAY NO! It is ok to put yourself first. As long as you keep giving sounds like they are going to keep taking. Tell your friend from now on you are turning your phone off at a certain time.
Also, when someone ask for something like money all you have to say is I don't have it. You owe no excuse why. Friendship is a two way street.
When I finally started putting my foot down about things I felt so enpowered over my own life. It is a great feeling.
This doesn't mean you can't help pple. It just means it's ok if you don't want to. It is always good to help pple out but when it enter fears with your own self then you need to change it.

Good Luck!