ESA re-assessment

Has anybody heard of re-assessments on ESA. I have been in the work-focused group for two years and recently my partner went to college. When she left my claim she lost carers allowance and I was told I would have to attend another medical in February 2012.
As a side note I was also told that as I have been on conribution based for over a year it will stop anyway. I asked if I will be automatically transferred and I was told "no, it doesn't work like that, you'll habe to claim again"
I am really lost here, can anybody advise please.

Thank you Gordon

I probably didn't explain myself properly. I understand about the 1 year limit to contibutions based and that mine will run out.
What I was unclear about was why after 2 years do they suddenly decide I have to go for another medical, simply because my partner left the claim.
I presumed I would be eligible for 'income related' but I was told 'it didn't work that why and I had to re-apply', hence the medical.
I am sure that my case is what they where trying to avoid. The work related group is supposed to help you get back into work. I did the interviews, signed up for permitted work but became to ill so I couldn't finish. I was told that I could not stop and the year had to run it's course. In that time the Pathways to Work staff where made redundant and i fell through the system.
I think that is why they are trying to get me to go to another medical & re-apply. That way, I won't be a burden to the system.
As an add-on, if the NHS had the funding to aid my recovery I wouldn't be in this postion anyway.
I just wondered if anyone else had been called up for additional medicals, after being assigned to a group?