I drank lemon water this morning and when i went to the bathroom there was blood on the toilet paper. is this normal?

Blood on paper: Blood on paper may be due to a number of reasons, and the color of the blood is the important factor. If you have never had this experience before it may be nothing. If concerned i would see my dr asap to discuss the situation to determine a cause. There really isn't enough info here to tell you more than that.

Abnormal: And likely unrelated. In urine or stool? Different causes.

Unrelated: Blood in urine or stool is not normal and needs to be evaluated by your doctor, since you are a female are you on your period?