Gone to pot

I have probably had the worst lesson in about 4 months. Everything i did tonight went wrong. Mounted the kerb twice, kept forgetting to check my mirrors, going too fast for corners, almost pulled out on a van on a island, wrong side of the road etc etc. Since I booked my test my driving has gone downhill. Obviously I'm thinking of my test. I'm not nervous about taking it just it's playing on my mind. Tried reversing round the corner, couldn't get that right at all, kerb one time, second time too far away. Selected the wrong gear on more than occasion. Kept going down the road too fast in tight areas. It's really pissed me off cause there was things tonight i did right. My gear changes were very smooth but my overall awareness tonight was shocking. I need to snap out of this cause last week wasn't very good but it was a hell of a lot better than tonight! Probably put this down to a one off. I'm giving myself two more lessons and if I haven't got out of this I'm gonna cancel my test for a few weeks. I know I'm almost there and having lessons like this feels like I'm gone backwards. Even my instructor said so, but he also said everyone has bad lessons, and it always happens before their tests. Lets hope so. T.L.M.S