The GP should never prescribe anything - they don't have the skills to make sure that things are done safely.
I'm afraid that the GP is talking utter bull shit - you are entitled to a referral now, although, if it is found that there is nothing "wrong" and if you haven't conceived by either the two or three year mark (and this depends on where you live) then you won't be entitled to IVF until that point. Basically, you need to have either a two or three year conception delay before you can have IVF. However if may be that there could be other treatments that are available to you that aren't as complex/expensive as IVF.
Obviously if there is a reason for a conception delay then treatment can be offered sooner.
I'd recommend that you have your early follicular phase bloods done (this should be LH, FSH, oestradiol and testosterone) and be between day 2 and day 5. Then you need to have a repeat progesterone 7 days before the expected onset of a period (so with a 28 day cycle this should be day 21). It would also be useful to have an ultrasound scan to check ovarian morphology.
Regardless of the results you should be referred to a specialist. If you want to pm me where you live I might be able to point you in the direction of your local fertility treatment policy and details of where you can be referred to.
In the meantime, the advice is "the usual": make sure that your BMI is between 19 and 30, take folic acid daily, if you/ your partner smoke then stop (these last two points are likely to affect your treatment entitlement) and if you drink alcohol do so in moderation.
On the more "human" side of things, it's a bloody difficult thing to go through. Try to make plans etc as you would normally do, get as much support as you can and, in the nicest possible way, don't forget to live. It is one of the hardest things to do, but the more "normal" you can keep things sometimes the easier it is to cope with.