If your profits will increase after paying a new hire, then absolutely, positively, go for it while you can. It is so difficult to work yourself into your current position that you must maximize your return while there.

Also, if you have more business than you can handle, then the only certainty on your decision tree right now is that you will lose revenue if you don't hire someone to help. Google may hose you (and that may even be likely, at some point) and you may be able to find alternate traffic streams, but they are not certain occurrences, nor is the timing of any of these scenarios (including a Google hosing).

And, of course, if you get help then it may free up some of your time to pursue the other streams without impacting your current revenue.

If you can mitigate your hiring risks by offering 1099 or contract-to-hire, or otherwise, that may be prudent.

But, again, you gotta' maximize your profit while you can. Congrats on having a "good problem" and best of luck!