My son had a pill I can't seem to i.d. It's a white capsule shaped tablet. One side has no imprint at all. The other side has what appears to be a capitol letter 'I'. However it has the line on top and bottom of the letter 'I' (capitol i NOT an L) Next to it is a '9'. However if you turn it upside down, it could be a '6 I'. I can't find it anywhere and I'm worried.