Your mother, Niobe, a foolish woman really. She demanded statues of herself and boasted about having more children than the goddess Leto herself... big mistake.
While your mother went on and on about have 14 children, and Leto only having two: those two children just so happened to be Artemis and Apollo. And the two were defiantly not having it; they took offense to her words. Who did she think she was? Their mother had suffered so many indignities already... so many hardships just to give birth to them.
So the two decided to relieve the burden of motherhood itself. Their arrows rained down upon your siblings. Artemis's killing painlessly, Apollo's a sudden fever.
Apollo brought the end to all seven of your brother's mortal lives. Apollo's golden arrows struck them mid-stride as they raced through the palace grounds, felled them as they wrestled in the training yards, silenced their joyous shouts mid-air. One moment, vibrant life pulsed; the next, stillness.
While Artemis, goddess of the hunt, brought the end to all seven of your sister's mortal lives. She, however, gave them a short and painless death out of pity.
There was no escape, no reprieve. Each impact a stark punctuation mark on Niobe's arrogance. At this point you just accepted your fate. Leave it to the Olympians to punish the children for something their parents had done.
But nothing happened. You stood there unharmed, Artemis had her bow pointing toward the ground, Apollo standing next to her with his own. They were deciding whether to let you live your life with the grief or losing all of your siblings, or simply just kill you and send you to the underworld as well.