You should try to clean your juicer once a week and by adding fruit it will help balence it out. The celery sticks may also be the problem.. sounds icky on my end but what ever works for you. Stay happy and healthy love! Good luck finding answers.
Perhaps, the ingestion of so much fiber at one time "threw" your digestive tract off kilter. High dosage of any "foreign" nutrients/substance (that which the body is not acclimated) will cause such reactions: whole milk vs low fat milk, vitamins, minerals, fiber, sugar, etc. Hope this helped.