You had a run in with a bull shark?
Yep, while diving with my dads buddy off of Salhalla Island in Oman. 50-60ft of water, patchy reef stuff. Plankton were heavy that day, maybe 50ft of visibility. There were 3 of them, chilling on a sand bed. The 2 smaller ones took off immediately once they saw us, but the larger one (maybe 9ft long) started circling us and did the whole 'arched back' swim. He snooped us out We ducked under a coral ledge and chilled until we were down to about 3 or 4 min of air, then made for the surface like Tridents, waving like crazy for the boat. I pissed my suit the first close pass he made, I'm not afraid to admit it.
The other time was years later, back in the States. I was fishing off of the ocean side of Islamorada, down in the Keys. 'The Hump' is a little mountain of sorts about 12 miles offshore, just loaded with amberjack, grouper, and snapper on the bottom, with tuna, wahoo, and dolphin on the surface. We were in my dad's 25ft Blackfin, and had heaved-to to stop and eat lunch and take a quick dip to cool off (it was prolly about 95F that day, and no wind at all). My bud and I were kinda goofing off, dunking eachother, swimming under the boat and stuff, just enjoying the 80F water. My dad is resting on the transom having a cigarette, then calmy announces, "Ok, lunch is over, time to get back in the boat! Let's fish!" We took our time getting back in, swimming to the stern and using the rudder as a ladder. We get in the boat, and not 20 seconds later this HUGE fvckin lemon cruises by right next to the boat! He circles the boat twice then disappears. We're sitting there swearing and shaking, and no one notices a commercal amberjack boat coming up behind us - it's captain yells out "Are you guys fvckin nuts?! Did you see that thing?!" My dad smiles, nods, and laughs at us, tells us the shark was there for awhile, but he didn't want to alarm us as our frenzied swimming back to the boat could have made things worse. This was the same place that girls brother got bit at, by the same kind of shark. My sister informs me he was doing the same thing, just cooling off, except he was in snorkel gear and it was a family outing in a party boat.
Anyway, those were my close calls.