My girlfriend hasn't had her period in 6 months and she says she has lost her sex drive.Anybody have an answer

We used to be able to do sexual things all the time and now nothing turns her on.My girlfriend hasn't had her period in 6 months and she says she has lost her sex drive.Anybody have an answer
If she hasn't had her period in 6 months she may be having a hormone inbalance. She should see a doctor.
Pregnant?
It's time to take a trip to the clinic. She might be pregnant, and it has two effects on your sex drive; either you want more all the time or you don't want it at all.
She should consult an endocrinologist. If her tummy is not bulging by this time, pregnancy is not suspected. More likely, with the loss of sexual drive, she is having some hormonal imbalance. Most of the time, thyroid problems result in loss of libido and irregular menstrual periods.
Explain everything to the endocrinologist and she will probably run a test on her thyroid hormones to rule out the possibility of hormonal problems.
You didn't mention her age (menopause?) or if she is taking any medications that could be affecting her cycle. Some medications can decrease sex drive and mess up hormonal balance.
Also, a few more pounds wouldn't hurt.
She needs to see a gynecologist.
I am willing to bet that her periods have stopped because she is way to underweight. I am 5'5 and at 115lbs people ask me all the time if i have an eating disorder! Being that underweight can also cause a severe case of anaemia which also can cause your periods to stop, my advice is to get her to a doctor. Going that long without having a period when no birth control pills are used is not a healthy thing.