Hair Color help!!!

I have a question about my hair, first here is a little history on my hair.
My original hair color is a dirty blond color, I started coloring my hair when I was 13 and I am now 28. I used to get my hair professionally highlighted and I loved it but it got too expensive and I had to stop, so I started doing my own hair. About a year ago I decided to go platinum blonde and started to do double processing, well after a while my hair always took on this ashy/pink/lavender tone, so I decided I was tired of the ultimate blonde color and for about 5 months I have been trying to get back to my natural color as close as possible but every time I color my hair, no matter what color it is (I never use ash) the roots turn super brassy and the ends always turn ashy in some way. Well about 5 days ago I tried a color that was called Tan Blonde by wella and it had an orange/red base, I applied it only to my ends (even though I got some on the roots) and I left it on for about 35 minutes. When I washed it out the ends were almost a caramel color with some pink/lavender strands. I am at a loss of what to do next, should I just stop coloring my hair ( I do it about once a month, or every 3 weeks as my hair grows fast) or should I go and see my hairstylist, I would love to do it on my own and save the money. Sorry this is so long but I need help...