Greetings kathy, and a warm welcome.
Spanking for pleasure is regarded as a "kink" so by definition lots of people will view it as "abnormal". Does that make you as a person abnormal? Absolutely not! I would contend that the majority of people have some form of kink even if a large number never move out of fantasy and into reality.
And the reason you can find spanking pleasurable can be scientifically explained. I do not know what proportion of people are capable of experiencing that pleasure under the right circumstances, but am sure that if people were taught how to achieve it there would be a lot more with the same kink.
Just in case you do not know (and because I like showing off my knowledge!), the reason is that the body reacts to pain by producing endorphins which are the natural pain killer. When done correctly the amount of endorphin released into the body can give a "trip" many times more powerful than hard drugs.
VV