Which is better: side quests after killing the warrior or Playthrough 2?

My question is, once I beat the warrior should I do all the sidequests in Normal before starting TVHM or should I go right to TVHM once it becomes available?

I just bought the game and have been playing with some friends who are higher level than me so that we could enjoy the Tiny Tina DLC together. As a result, I leveled up pretty fast without doing much of the main story quest or side quests.

Now I'm a level 32 commando and haven't finished the main storyline in normal (Just finished "Where angels fear to treat Pt 2"). I get almost no XP from kills on missions. I still have tons of sidequests. I imagine some of them might give good loot, or be fun to play. It it better to go to Playthrough 2 or should i do the sidequests in Normal first?

EDIT: changed question title and some wording for clarity

Thanks to the comments to my question above, I think the question has been answered.

Playthrough 1 sidequests don't adjust to your level after beating the warrior. So it doesn't make sense to go back to sidequests in Normal since enemies and quests will be too low level. (As per @fbueckert)

DLC quests do scale so it does make sense to do these quests in playthrough 1 (Normal) mode before heading to Playthrough 2 (TVHM). (As per @Reafexus)