How do I overcome my phobia of swallowing tablets?

CBT. Seek a cognitive-behavioral therapist who specializes in phobias. One method they use is systematic desensitization which slowly and incrementally brings the person closer and closer to the thing they are afraid of in slow, graduated steps that help make the anxiety more tolerable.
I know a few tricks. There are a few tricks to swallowing pills: 1) try to practice with small candies, like m&m's or tic-tacs, 2) always take pills with a drink or water. Trying something sweet like orange juice can increase saliva and help you swallow. 3) you have no taste buds under your tongue, so if you place a bitter pill under your tongue and then swallow it with water or juice, you won't taste the pill at all.
See a Psychologist. A true phobia such as this usually requires professional help. Realize that you are not "crazy." you are just looking for help to overcome an annoying restriction on your life.