I have found that my hair dye is only lasting for just over a week. Any suggestions??

If you are going blonde you can try using sun in but I would be careful using it a on already dyed hair

Check your packaging and see if it says semi-permanent or temporary. Permanent dyes shouldn't wash out that quickly.

But if your subject line is your real question, there are a lot of different standards, absolute bare minimum emergency damage control dying can be done in as little as two or three days between, the general rule of thumb is at least 14 days before doing anything to change your hair color.

If you are NOT using something with an automatic lightener or anything that requires bleaching, once there is no remnants of bleeding color should be fine to dye over it.