Esa to uc query

Hi so I've migrated from esa to uc im in support groupdone this within the time ,my question is got a payment of £166 on thursday the day i would be paid normally ,i got a letter today saying it was my final esa payment,surely that can't be right i get £760 a fortnight normally? This was for 13 days esa,the next question is i know housing benefit continues for 2 weeks i have already had a letter from council saying my discretionary payments been stopped and I owe rhem£50 overpayment,will I be in rent arrears by the time this is sorted out and how can they expect a couple to live on £166 for 2 weeks really sorry if this doesn't make sense but I'm so so stressed with it all x