I recently started a new job. A new job which requires a long and rather frenzied commute, followed by a day of brain melting training, followed by another long and even more frenzied commute. I'm surprised I don't have brain cells leaking out my ears.
Does this mean I've stopped writing?
No. Hells no!
Granted, my writing is currently taking a slightly different form. I'm not sitting down at a keyboard pounding out chapter after chapter. Instead I've got pen and paper in hand (Yeah, I'm old school like that.) and I spend my free time at work plotting and planning and really getting the plot and characters nailed down. That way over the next few weeks I can do a bit of actually writing every single day. Since everything will be plotted out, I won't have moments of "Now what???"
Ok, I'll probably still have moments of "now what", but hopefully they'll be fewer and further between. Which means the ability to write faster and hopefully retain a greater number of brain cells. Which are useful. Mostly.
I guess my point is, when the going gets tough, you don't give up. You just find creative ways of making your schedule work for you and your writing.