Getting started for what feels like the nth time

Hi,

I'm looking for some tips on how to get started properly after a very long time out of the gym. I've not been training properly since July last year and whilst I was a bit overweight at 15stone I could run long distances comfortably (6-10 mile range). The two years prior to that I ran the great north (half marathon for those outside of the U.K.) run 2 years in a row both under 2 hours. Up to July last year I would exercise regularly (run 3 times per week and gym 3 times per week) and at that time I ran a 10k road race and pushed myself a bit too much and ended up taking time off, only a few weeks but enough to lose a lot of conditioning and i suffered disappointment of not being able to run the great north run that year which meant I took more time off through lack of motivation.

Ever since then I've been stuck in a viscous circle where I will exercise for one maybe two days a week - gym work only which would consist of an hour cardio and an hour doing weights. But I would end up mega tired for days on end and when I get really tired I binge eat. Having a stressful job doesn't help either as this adds to my eating problem when I've had a bad day (my job is a sit down job as well). I'm now up to 19 stone which was my starting weight when I first started several years ago and whatever I do doesn't seem to be right. Each time I'm in the gym I try and do the same volume of exercise but lower intensity but even then I still end up tired for days on end.

Is this mind over matter or should I scale the exercise back to an hour for a couple of weeks to let my body get used to it?

I'm happy to post an idea of what my diet looks like on a 'good day' if needed.

Thanks