It's obviously intended to be ambiguous, but the more "realistic" (...if you see what I mean... it is sci-fi after all...) answer is that it's all his recall trip, OR that the people telling him so were right - that the Recall clinics are "butchers" and "****ed up his mind" (leaving him in a permanent catatonic state, "on vacation" forever).
It's really too much of a coincidence that the events follow so closely what's described by the travel agents at recall, and that his love interest fit his specifications at the start.
Then again... you could argue that he picks his vacation because he subconsciously remembers his past life and so is drawn to it - and that he describes Melina when asked for his "perfect woman" again because he subconsciously remembers her. Then again... it of course transpires that Hauser was working for (or even partners with) Cohagen all along and was just using Melina, so would she even be his perfect woman?...
...it's a great film either way. I spent half of my childhood watching Arnie films - I probably saw Total Recall for the first time when I was 8 or 9
"The Running Man" edges it out as best "classic Arnie", though. Some pure 80's action cheese right there.
Threaded Mode