Restore Healthy Hair Growth, after a Hair Cut

Help, I usually do my own hair in between relaxers and go to my fellow dominicans when I get frustrated, and have them trim my ends )which I know you should do with each touch up and I don't) Well now you will see why, I always have this problem I tell them trim and they cut, they cut my hair so it is all the same length, which is bad for me as one side is longer and grows faster than the other. So here we go again, I feel bald, no ends, no pony tail, and I always worry it will not grow back. As we get older Im not sure our hair grows as fast or as healthy. Correct me if I'm wrong, and my diet aint that great either, so how do I get it to grow back to at least where my bang is back to my chin, and have an ample amount of hair to style, I never had shoulder length hair, just slightly above, now it looks like a minature bob, its dry and course (not usre if this hot sun and heat killed it this year).. Its just these so called trim sthey give me look godd at first, then I cry at how short they made my hair, then the stylin problems set in and the dryness, and not holding curls like it use too with a healthy bounce, Please if you experienced this or cut hair and have skills and how to get it to grow back, etc.. let me know. I also hair our hair grows in the summer and breaks in the winter? I like dom. hair products, use pantene, etc.. perm I use olive oil now as it does great for gals, but prior i used motions, affirm, and creme of nature. Are the dom. perm products good? I just need a new regime from perm, shampoo, deep cond, rinse etc.. and especially with the dryess, something that keeps it looking sleek but wont make it heavy and too oily, yet my curls will hold up with this heat. HELP.. Your 411 is appreciated.