Had 3 fillings now have severe pain????

It is not uncommon to have some dental pain for a few days after dental fillings.   If the pain is constant,   And in sensitive to cold and the symptoms linger you will probably need rootcanal therapy. Luckily rootcanal treatment is very easy and you can have your dental treatment can be completed in one day.  

If the restorations that were placed in your teeth were deep ones due to the decay of the tooth, it is a possibility that you could have affection of the nerve. Please visit your dentist so they can further evaluate if there is a possibility that you may need root canal therapy or other options. 

Feeling some sensitivity in your tooth after a dental filling is not uncommon, especially after treating deep decay or replacing big restorations. Usually the sensitivity lasts for few weeks and gradually goes away. If the pain persists or gets worse, it might indicate a damage to the nerve of the tooth. Your dentist is in the best position to determine the cause of pain.