short luteal phase

Danielle
Hi everyone.
Having a right nightmare as the past few cycles i have been spotting 3-4 days before my full flow period.
Obviously I googled it and everything points to short luteal phase
I called the doctor this morning and he basically laughed it off. I'm in the UK. 
Has anyone had a positive pregnancy experience with a short luteal phase? I've diagnosed myself with infertility and now can't stop worrying! 
Thanks for your help :)