Am I being like bipolar or something?

Whenever my boyfriend and I go out, he is always really affectionate, like holding hands kissing me, stuff like that. But then like midway through the date or towards the end, I get annoyed with the affection. Am I being weird? How do I tell him when it's too much affection? He won't leave my side the entire time, even if we are with friends and I just want to be able to talk to my friends without him always trailing behind me! Could it be that maybe later in the relationship we won't be as affectionate, is it just the "oh new bf/gf, we have to be affectionate all the time", will it wear off? help?