Yes, as Cheeky Chops says, unfortunately you cannot bring an unfair dismissal claim.. WIthin the first year employers can dismiss you pretty much for no reason at all.
However, after 7 weeks you should have been entitled to some notice (depends on your contract but i think the minimum would be a week- Buildersmate will know), for which you should be paid. Also you would have earned some holidays, so if you haven't taken any you might be able to ask for holiday pay as well.