she cries for hours and hours if I dont hold her. So what I do is put her in the crib and let her cry?

I don't have any kids as of yet, but my friends do.  Have you tried putting her in something that rocks her.  That might sooth her.  Also, my mother used to put a small ticking clock in my crib and she said it reminded me of being close to her.  It was as if I was hearing her heart beat.

Good luck.

I've seen this act from my nephews and nieces. If the baby is used to being held all the time, it will look for that.

 This may sound cruel and I can't probably do it but I've seen that as long as the baby is fed, dry, and rested, you can let the baby cry. Leave the baby alone for 20 minutes. Over time, it will stop crying :)

My kids have each gone through clingy stages. Basically you either hold them or they cry. I've always chosen to just hold them. Heaven knows that they won't want me to hold them in a few years. I try to rmember that and just enjoy them wanting me so much - although I know it gets hard when nothing gets done! I've had sick kids for the last three weeks (we've been passing a bad cold around) and I am so far behind on things like laundry that I don't know if I'll ever catch up! It was nice to have them want to be that close to me though :)

 Hey Munchkins Mom! its me Amanda (aka Navygirl908) from the old forum how are you?

to the OP I am having that same problem and I agree with MM if you hold them or keep them close they will "meltdown" a lot less when you are out of sight. Mine get so tired of me holding them that they fight to get away and then I run to do some chores that I have had to put off because they were clingy. Have you thought of a carrier? Sometimes that is best so you can have them close and still keep hands free. 

God Bless

Amanda