We just went through the same thing! My 7 month old would only want me and would cry and scream if I tried to leave her sight or just set her down for a minute to take a break or get something done. It was starting to hurt my boyfriend's feelings because she would do that even if he was holding her or trying to play with her. I admit I liked that she wanted me so much so I let it go on for a day or two before I let my boyfriend (who works with children and is currently going for his master's in psychology) take charge and do some behavioral corrections.
First you have to realize that crying is not going to hurt her (it hurts you more than her because no one likes to hear their baby cry), if you set her down and she starts crying and screaming, you have to stand your ground and not give her any attention-don't even look at her-while she is throwing her fit. If she pauses, even for a moment, that's when you take the opportunity to comfort her and give her affection. If she starts crying again, you stop again and do not give in until she stop crying (again, even if it's only for a second). It was so hard for me, but it did work.
As for the napping, we're using the CIO method and it's only the second day and she seems to be on board already! We put her in her crib and she'll push herself up on her hands for a while looking at the door for us to come get her, but then she's so tired she gives up, lays down, and finally falls asleep. It's all for her benefit in the end, it's best to teach her to be a little self-sufficient in basic things like sleeping. I really hope this helps. Good luck!