Light period on clomid?

So last month I was on my first round of clomid 100mg, pretty sure I ovulated as I had ovulation pain and positive opk, not getting any blood work done so won't know for sure. Anyway when I was expecting my period it was 4 days late and when it finally started it was so light I couldn't even call it a period I didn't even need a pad so I guess it was spotting. The spotting lasted about 5 days but stayed very light through and through. Is this a side effect of the clomid? Has anyone else had this and do you know what caused it? I called my doctor and was told not to do clomid this month due to not having a normal period.