Why does my hair fall out a lot?

ok lately I noticed that everytime I wash my hair it tends to fall out alot and also when I brush it after I wash my hair.

Now im trying to let my hair grow out because :

1. ever since my aunt has been diagnose with breast cancer and had to lose a breast due to it ( shes doing fine now ) I promised my self id grow my hair and donate it to those who have cancer and is going through kemo…. now i know they want natural long healthy hair so this is why im letting my hair grow out to get the black out of my hair

2. I had dyed my black with the box dyes you buy at walmart or shoppers the hair dye I use was natural instincts clairol …. now there is 2 kinds one that comes in a gold box which is supposedly not permanat and a silver box which is the permanant one. I used the gold box is says it lasts up to 28 shampoos which means after 28 shampoos it suppose to be somewhat all gone right? ….its now august and i still have the hair color in my hair , and this is why im trying to grow it out to get rid of it

3. I usually dont go to the salon after 3 months to get my hair trim ….but i have been lately to do this promise i made . my hair gets easly damaged with split ends so to do this promise im getting it trimmed not only to get the black out of my hair but also to maintain it from splitting

heres my problem i been noticing my hair falling out alot since i think it was a couple months after i dyed my hair

now:

1. my hair isnt dry or britle as i have a problem with oily hair … which brings me i been having a problem lately where even after i shower and its been dryed theres a patch of hair ither where my bangs are or at the crown of my head that still stays oily and its also sticky ? doesnt matter how many times i try to wash and rinse my hair out it doesnt come out…. now this doesnt happen all the time but when it does it stays for along time …what can be the reason for this ? …. i used baking soda and the vinegar wash and it seems to help it but i dont want to have to keep doing this every time i have this problem

2. i use to wash my hair every other day because i have oily hair…. but my hair stylist suggest i try to go as long as i can with out washing my hair ….which i do if i know im not going to be going out for the next 2 or three days even when i go to work i just pray some body mist in my hair and then tie it up. so over washing it isnt a problem here

3. I never use blow dryers, or hair straighteners during the summer as i find there is no point since i keep my hair up especially when my hair is long now…so over drying and straightening is out of the picture aswell

Now im not balding anywhere but my hair isnt as thick as it use to be… Im not stressed or at least i dont think i am? I know i dont excersis but i try to be as active as much as possible…. im thinking of hitting the gym sometime in the fall because as of now i cant due to other things getting in the way, once i get the resovled ill be getting my daily excersis I try to eat healthy but i notice i dont eat alot of fruits …. i havent been doing so for many yrs now and this problem has only start recently back in may so i dont noe if not having my vitamins is the issue ? one thing i do have an issue is my daily in take of water …. i have a problem with drinking water can this be an issue ? also the types of shampoo’s i use are head and shoulders which i tend to use daily well sometimes …fructise shampoo clean and fresh 2 in 1 shampoo and conditioner i also keep my hair up in a pony tail or a bun its never down and i brush my hair when wet with a regular brush

what can i do to stop my hair from falling out ? what can i do to make my hair thick again ?

its alot to read and many questions to answer but if someone give me advice on this id appreciate it alot