[Marwan]

to give you a short answer, YES its dangerous to go on your own, among the dangers are:
1 - You could get entangled at the bottom as you attempt to extract a holed up fish
2 - You could get a cramp (even if you are fit, dehydration can cause that) and be unable to swim back
3 - A buddy can look out for you if there are marine hazards in your area, sharks and boats are 2 good examples..
4 - You could blackout for pushing yourself beyond your limits, your life will then depend on someone pulling you to the surface immediately and doing the necessary steps...

having said that, you could do some things based on the conditions you outlined:
1 - Always tell someone on shore (possibly from the hotel if they have a lifeguard), where you will be exactly and when you intend to return..so that they will look out for you
2 - Always have a float and flag that are visible even in surf (log flag pole)
3 - Always take a bottle of water with you on your float, if you could put some fruit thats good too (oranges tend to have a good resitance to water)
4 - Keep the fish stringer on your float and not on your belt
5 - Rig the gun in a way to lbe able to ditch it in case of any danger/entangelemnt..reels or attaching the gun to the float (my preferred option) are both good options, their use will depend on conditions where you hunt...
6 - Have a spare gun on the float if you have another gun..
7 - Dont eat heavy food and DRink lots of water before you dive

thats basically what i could think of at this point