I have a bad case of allergies since yesterday. I have been taking Claritin (loratadine) (cvs verstion) once a day. It doesn't seem to help. Ideas?

Other options. If you are sure your symptoms are allergies and not a viral upper respiratory infection, you might want to try a different antihistamine such as Allegra or zyrtec. Sometimes one antihistamine will work better than another. Nasal steroid inhalers are frequently more effective, but you will need to see your doctor because these are prescription medications.
Bad case of allergy. At this time of the year most likely you are allergic to pollen (trees, grasses, weeds). Antihistamines like claritin, (loratadine) zyrtec, Allegra are all helpful without causing drowsiness. Unfortunately after a while they may quit working. So proper evaluation by a trained allergist may help. Allergy injections or immunotherpy to build up your tolerance to pollen are most effective in the long run.