Hello, fell running compatriots.

I'm due to embark on my first ultra marathon this time next week; the 'Clyde Stride' - 40 miles along rather flat roads and pathway ("spare us", you groan).

Anyway, in all honesty I am probably underprepared. My longest run in training is 22 miles (a few weeks ago) and in the last couple of weeks before taper time I was finally pushing 50 miles a week. The thing is though; every run during the last couple of weeks felt terrible. I didn't enjoy them and I struggled. This has now given me the fear; 'I'm not capable if doing this', 'Im going to fail miserably', and so on. I was just wondering if this daunted, worried mentality is normal before a first ultra, or am I genuinely underprepared?

Answers to my running angst-ridden drivel greatly appreciated!