I have a friend with a 7 month old, and her daughter sleeps pretty much the same way. Some babies have difficulties sleeping, I know mine did, he only recently got into a good sleep and nap routine a couple of months ago (he is 20 months old). Since she is rubbing her eyes a lot, but not staying asleep, maybe she is uncomfortable (wet diaper, rough outfit, cold or hot). I know that my son would only sleep in his crib for a little while (no longer than 30 minutes) during the day forever, but then I started putting him down on my bed, and he slept for much longer naps. He also slept better when I slept with him (when he was younger), so I would take a nap with him. When we put some padding in his crib once he got older, he started to sleep a lot better, his bed was just too hard and uncomfortable. Not a solution for you yet since she is still pretty young, but it could be an issue as well. Since she is happy, she is probably getting enough sleep (she will be fussy if she isn't getting enough), you just want to get it to be for longer periods.
When you say she is eating 6 meals a day, do you mean breastmilk, or solids? She should not be eating more than one or two solid meals a day (really small meals, like a tablespoon or two of something). Maybe she isn't getting enough breastmilk because she is filling up on solids, which have a much a lower calorie count in comparison to breastmilk. Also, if she is crawling and very active, she might need more breastmilk, which is why she eats every 2 to 4 hours. My son nursed as often at that age, and probably up to 10 months old. Every baby is different, she might also be trying to go to sleep by nursing, so using the breast for comfort and not just milk, which can be fine.