Is she napping?
She sounds real over tired.
Also she is hitting some milestones... at this age they start crawling/sitting up/rolling over etc. And even in their sleep, it is an impulse that they do and cannot control. Babies have no impulse control. And it is instinctive in them, to do their new skills. Even if when supposed to be sleeping.
It being a phase... until they develop more command and mastery and at-will control over their appendages.
They can't do, motor-skills wise, what they 'think' they can. Hence frustrations.
At 6 months was also a growth-spurt time. Does she get enough intake and is feeding on-demand? A baby needs that.
For the 1st year, breastfeeding or Formula is a baby's primary source of nutrition and intake, not solids and not other liquids.
AND teething, occurs at this age too. Which affects their sleep.
MANY things occur in a baby, at this age. And it occurs, all at the same time. So its hard for the baby too. Growing pains.
When not feeling well, a baby does get more needy and frustrated.