You can use the phrase "for weeks now", "for two days now", "for 5 years now", and so on. When you use the word "now" after a length of time, it shows that you think this was a pretty long time. Not a really long time, but maybe longer than you expected. For example, if you're telling someone how long you've been studying English:

I've been studying it seriously for over three years now, but there are still little things that trip me up.