Hmmm... these are good questions.
I've heard that you should always color a perm, not the other way around. So that means you should relax first and then color afterwards. The advice Tracy aka LHCF Color Guru gave me that wound up saving my hair was to wait at least 2 weeks before coloring...and then wait 8 weeks from the coloring date before relaxing. It may seem tedious, but it's not. Even the stylists at the salon were amazed, saying they'd never seen hair my length (at the time, nape length) that was so healthy after being relaxed and highlighted. In the meantime, if you really need to color your hair dark, why not use a rinse? I've only used Sebastian's Colourshines (aka Cellophanes) but others on the board have also fared well with Adore.
If you have lots of new growth, why don't you relax it? That way, when you get a trim your layers won't be messed up (like they might if you get a trim pre-touchup). Don't extend a relaxer just for the sake of extending it. Some of the LHCF longhairs relax every 4 months, some 3 months, some 8 weeks. It's about whatever your hair requires.
It sounds like you're frustrated. I can relate. In the meantime, if you can, douse those ends with moisture and tuck them into a protective style (a bun, a drawstring phonytail or a french twist) so they won't be exposed to the air (which is drying) and won't be subjected to unnecessary friction, brushing against your collars, shirts, coats, bag strap, seat belt, etc. The bonus is that since your hair is tucked away into a nice and neat protective style, you won't be able to see how awful it looks (it may or may not be as bad as you think). Good luck, Felicia!