Is bbt useless? No such thing as short LP?

Just back from seeing a GP because we've been trying for 12 months with no luck. 
I took my bbt charts and she didn't even look at them and said bbt is useless. 
She also told me it's impossible that I'm averaging an 11 day luteal phase because it is always 14 days. 
Thoughts?
P.S. I was referred to a specialist anyway, but wanted to see your thoughts :)