Secondary infertility..?

Hi, I am completely new to mumsnet but I wanted to maybe start chatting with some other mums (or mums trying to conceive)
So here is my story..
I already have a beautiful little boy, he's 4. He was a complete surprise as my periods have never been regular and I though perhaps I might have problems. We weren't trying as such but also weren't using protection. Had a normal pregnancy (though he was big, he was 4 weeks prem and still weighed 7lb 15oz!!)
When he was a year old my husband and I decided to start trying again, came of contraception.. And nothing. 3 years of no contraception and no pregnancy. I went to the gp about a completely unrelated topic, but she asked about my health in general and I told her about my few and far between periods (usually 3 a yr max, I'm 24 and had my first one at 13). Ran some tests and said I possibly had PCOS (no other symptoms except no periods). Was sent to endocrinologist at the hospital, had more blood tests, had an ultrasound and no cysts so not PCOS but that was where it stopped, no further appointments, just left..
Found out I was pregnant in September of this year, but unfortunately had a m/c at around 7-8 weeks.. We were devastated. My sister is currently pregnant with her second so it has been really tough not being able to talk to her about it etc.
After m/c I spoke to my gp about possibly being referred to fertility clinic. Had a message back from her a couple of weeks ago saying that fertility clinic won't see me until a year after the m/c.. Unless there are any underlying problems! Which means to me they probably didn't even look at my history etc!
I know I should be happy that I have a happy healthy little boy, but I feel unfulfilled if that's the right word? I am so desperate to have another child (ideally I wanted 3!) I spend every waking hour thinking about getting pregnant, I am constantly googling.. I feel like I'm going mad! I don't even know if I ovulate regularly! It seems no one wants to help, every way I turn I am shut down.. All I want is for someone to say yes we'll help, or this is what's wrong.. I work in pharmacy so I know what medical help is available.. I just feel at a loss!
Has anyone been in a similar situation? Would really love to chat to anyone that has any advice etc.
Thanks and look forward to chatting : )
Bekki x