You are eligible for funding as 'course plus one'. If you are enrolled on the 4 year version of the course this is 4 years plus 1 year = 5 years (i.e. 5 years funding).
This allows a repeat year during the course. If you have taken 2 years funding to complete the foundation, you should still have 3 years left (i.e. year 1, 2 and 3).
Make sure your University has you on the 4 year version of the course and not the 3 year version.