I am not surprised by their response, here in the UK they tend to have a "wait-and-see" approach until 3 years old. I am surprised by the comment about eye contact (typical GP response I guess), as simple anecdotal evidence by just reading these forums (and perfect example by previous poster) shows that infants with autism can and do, in many cases, have excellent eye contact.
However, with an adjusted age of 17M, while on the late side, he is still within normal range for pointing and can still catch up in the coming month. Encourage him to point by keeping things (that he likes) out of reach, and by you pointing to everything in the house (say 'look' and point, he should hopefully be able to follow your point). Normally they will start pointing to interesting things in the distance (like a plane in the sky) first, followed by pointing to request about two weeks after that. However, before they point they need to be able to follow you point. Once they realise the communicative power of pointing they will point in excess of 50+ a day! If he does not point BOTH to share and request by 20M certainly demand a referral as large studies have shown that an infant not pointing by 20M nearly always means autism.
In the mean time keep an eye for any stereotypical behaviour like unnatural preoccupations with lining/stacking/spinning objects, odd eye or finger movements, excessive negative reaction to change (fixed on routine), scared of everyday noises, food sensitivities (gagging on certain foods), inappropriate use of toys, lack of imaginative play (i.e. feeding his teddies, wearing a box in his head as a hat, etc), lack of interest in other children (like if they were invisible, only attracted to adults), deficits in joint attention (lack of a 3-point gaze when playing with him) and absent social referencing (looks at you when something unexpected happens, like the door bell rings).