All I can say is what everyone has also said . Practice practice practice for I remember when I finally got to my first barre chord F it took me alone 2-3 months to build up the finger dexterity and strength .
But for what it's worth what you're going through is what ever major guitarist out there went through also so don't give up . I've only been with GT a short time but I'm amazed at my progress and enjoying playing so much .