Hair dye gone after washing it

What colour was your hair when you applied it? Titanium looks very pale to me which means you’d need really pale yellow for it to show.

You definitely didn’t use conditioner when you washed out the bleach?

did you apply it to clean shampoo'd hair?? if you apply conditioner before th dye, it will not stick to the cuticle.

Thank you so much for your replies. Ok well I didn't use conditioner at all. I used Clariol BW bleach with a Volume 20. So my hair was a yellowish blonde. Do you think I need to tone it first before dying it? This happened to me before when I dyed my hair blue a few years ago, in fact after I bleached it I didn't wash it for maybe a couple of days so it can be slightly dirty, but same thing happened. Once I rinsed my hair pretty much 95% of the dye came off.

Yeah, yellowish blonde is too dark for what you used. In fact, all you actually did is tone it. Blue is also a tricky colour and needs to be very pale. They're both opposite yellow on the colour wheel so they don't interact with it well. What you need to do for those colours to work is get your hair to a very pale blonde. When the dye is too "pale" or "weak" (neither words are actually quite right, but close enough for now) to actually work on yellow hair it will seem like the dye just isn't sticking. All that's actually happening is that it has "stuck", it's just that it's too pale to see.

Also, dying on dirty hair is bad. You should be dying it right after washing it. Direct dyes don't need hair to be dirty, they need exactly the opposite. They basically stain the outside of the hair and they have nothing in them to remove the dirt, unlike permanent dyes. You have dirty hair for permanent dyes and bleach to protect your hair and scalp somewhat from the harsh effects and it eats through the grease and dirt. All you're doing when you use direct dye on dirty hair is stopping it getting to the actual hair to do it's job.  It won't be your full problem, but it'll definitely contribute to your problem.

Though, don't take that as an indication to bleach your hair again straight away! For now you're better living with the blonde you have and then trying again in a month to make sure your hair isn't too damaged before you go ahead.