While they're at diagnosing your problem from darkness, i would like a couple lottery numbers too.

you are asking a broad question, without having the patient ( your website ) and what you have done in the past couple months, how is anyone going to tell you what is wrong.

Check your analytics.

Where was your traffic coming from? Where is your traffic coming from now?

It could be a heap of different things but as above, your question is too broad.