No libido at 22 HELP!!

I NEVER DO THIS but.... I am almost 23 and I have been in a relationship for almost 4 years. 3 years ago my libido fell off a cliff. My sex life started very early in life being curious about my body and getting REAL friendly with my shower head since 8. I have been making excuses forever on why I am not "in the mood" I am hopelessly in love with my boyfriend but also tired all the time. Embarrassed to talk about my problem to anyone else. This should be my peak right?! Anyone else have this problem? Any suggestions?