I've recently been through this with my 7 yr old Dd too,she has had all the symptoms you describe.
We first noticed lumpiness in one of her breasts ,so took her to the gp to get it checked and he referred her to the hospital to see a endcrinologist(sp) to see if it was early puberty.
The consultant checked her all over and xrayed her hand,to check for bone age,as this gives a good indication of early puberty.
The consultant did mention if there's no body hair ie under the armpits or in the pubic area then theres less chance of it being early puberty.
She decided my dd wasn't going through total puberty but is having fits and starts.ie her breast buds will swell then stop again afew days later and said this is actually quite normal in girls of this age,as their hormones are starting to get ready for puberty. She is monitoring Dd on a 6 monthly basis.
The main problem we are having are the pmt like moods but on consultants advice I am giving Dd evening primrose oil,which does seem to help abit.
Both my Gp and consultant said puberty is 'hitting' girls earlier every year.
Try not to worry and if it puts your mind at rest get her checked with your Gp