Sometimes the only way you can actually care about someone is to let go. Not because you want them to go away, but sometimes that is the best decision for yourself and sometimes for you both. 
Love is not supposed to hurt! Love is unselfish, loyal and to have a sincere concern for others. When it comes very hard and you have to make it happen, that is not love. 
Love sometimes can be painful if it is not flowing properly. This usually happens when one has love and the other doesn't. Sometimes when you put in all the work and feel drained, that is when it is one sided. People think the harder they try, that will make someone love them. 
Sometimes love requires letting go and letting that person have room to grow and stop ourselves from going crazy trying to prove how much they love us. 
If I am hurting inside and everything seems "crazy," that is not love. That is usually me trying to make things a certain way that they are not meant to be. If it comes easy and with peace of mind then just maybe that is love. Love is not based on jealousy or control.
Love is allowing a person to be who they are, go where the want and do what they want, knowing deep in your heart that all is well. If you get a knot in your throat and a pain in your stomach that is not love and that is a sign that something is wrong. That is why loving yourself is very important. Who wants to feel pain? Most want to not feel pain. Others in life that is all they know and they mistake pain for love. Once again, love is not supposed to hurt.