I have three theories as to what you may have seen. It is difficult to pin down which it is, given your description, since all three events are so similar.
1 – Instantaneous Atomic Fission. Basically you could have seen an atom split causing a brief flash of light. As per your description, it must have been a smaller atom, probably a hydrogen atom, which would be plentiful right above a steaming hot bath. Instantaneous Atomic Fission, or IAF, is a very rare event. The odds of a person actually seeing it happen are astronomical, but given the billions and billions of atoms in our universe, you just got lucky.
There are many theories that attempt to explain the causes of IAF. The leading theory in this area is my second theory to what you saw.
2 – Each atom in our universe encapsulates an entire, yet separate, universe. And each of the atoms in that universe encapsulates yet another universe, and so on, etc. What you saw was the result of an epic battle between different factions in a separate universe. Apparently, one of those factions, either accidentally or purposefully, detonated the mother of all Weapons of Mass Destruction and wiped out the entire universe.
The results of this are quite saddening since not only all the life in that universe was destroyed, but the lives in all the universes that were in the atoms of that universe, and so on, etc.
Finally, an equally plausible theory might be:
3 – Alien Abduction. The purple flash that you saw was actually two purple flashes. Or, more accurately, the first half of the first flash and the second half of the second flash. You see, aliens are known for using stun rays that paralyze their subjects and wake them up again when they are done with them. Coincidentally enough, these rays are purple. They are kind of like 1920’s style death rays, except that they only stun you rather than kill you. 1920’s style stun rays, if you will. In any case, they zap you and you are paralyzed, stunned, hypnotized, what have you, then they transfer you to their ship and probe you in many unspeakable ways. When they are done, they transport you back and “unzap” you, leaving you to wonder what that purple flash was. You remember nothing unless you undergo hypnotic regression therapy.
This would explain any aches or pains that you may not of had previously. Did you experience any lost time? Probably not, since the Aliens are getting better at transporting people back through time so they don’t realize what happened.
You made an especially attractive subject to them. I mean, other than the fact that you were buck naked, but you weren’t wearing a bra. If you think men have a hard time with bras, you should see an Alien try to get one off. You know, they’ve mastered time travel, intergalactic travel, and (recently) insurance forms, but it is just downright funny to watch these guys try to get a woman’s bra off. A word to the wise: if you are really paranoid about getting anally probed by Aliens, try to figure out how to wear a bra around your ass.