Of course you were scared! That's a scary thing to happen.
Yes, it is possible for implants to fail. However, when one fails, that does not mean that you cannot have another one.
Does this dentist do implants?
Definitely get a new x-ray first. A failing implant will show bone loss on an x-ray. Also, the dentist should be able to get a sense when he "wiggles" it whether it is the crown or something more.
However, if this dentist does not do much with implants, you could ask him to refer you to a specialist. Since it's your front tooth, I highly recommend seeing a periodontist. A periodontist is a gum specialist who will work with your dentist to either remedy the problems on this implant, or work with you through a new one.
Because cutting off a crown is pretty invasive, unless your dentist is absolutely sure it's NOT the screw being loosened, you should start with having someone access the screw to tighten it. Once the screw is accessed, the periodontist will know for sure what the problem is.
Does that answer your question?