A lot of good advice here already. So my answer isn't comprehensive; it's just filling in some of the yet-unaddressed areas.
First, hopefully, you interviewed multiple Realtors before deciding on this one. Reflect on the process and what gave you confidence (or what raised some concerns) at that time.
Second, the interview process with a Realtor should involve the agent presenting you with some sort of marketing plan. For instance (and these are basic): Putting your home on the MLS, putting a sign in your yard, possibly holding open houses, etc. It should also detail other activities: brokers' open, advertising in publications, whether there will be a custom website for your house, etc. The question is: Whatever your agent promised, is he/she doing what was promised? At the very least, ask for regular (as in weekly) status reports.
Third, your questions deal in part with continuing agent follow-up and responsiveness. You need to talk to your Realtor about those issues--such as keeping in contact with the third guy. (As well as the first and second.) And here's a tip: If any or all of those three bought something else, your Realtor should find out how those properties differed from yours. That can be a clue as to what they (and others who haven't even looked at your house) found unappealing.
Fourth: As already noted in the answers (but worth repeating) 3 showings in 23 days isn't much in most areas of the country. Admittedly, it might be OK where you are. But ask your Realtor. And, unfortunately, the answer to few showings is usually (though not always) a price cut.
Fifth: Get more advice about the pool. The pool will scare away a lot of families with small children or pets. However, in some areas of the country, a pool is a really desirable amenity. You have to find out what it is where you are, and then act. Right now, you've got the worst of both possible worlds: (1) The frightening pool scaring away some families, and (2) A non-functioning pool for people who want a pool. Either offer a functioning pool (that is, you have it fixed) or fill it in, create an attractive back yard, and make it more family-friendly. [No: You can't say "I'll let the buyer decide which way to go on that." That doesn't work.]
Hope that helps.