If just a one time thing on first try it shouldn't be a problem. You need to check with your school's policy about shelf retakes.
My school is similar to the above in that you can fail I THINK up to like 2, and if so you have to retake them towards the end of the year when they offer retakes. If you fail them again though you may be delayed moving on to 4th year and graduation date moved back until you do some sort of remediation.
Big picture though, don't freak out, don't stress too much. Just check with your school and see what the next step is. Also need to figure out "what went wrong". What resources did you use? Did you honestly spend as much time during the rotation studying as you needed to be?