If it's just the top flopping over, that's normal, if it's the whole plant then I'm not sure what would cause that, but git a stick to support it.
Give it some tomato feed and see if it improves.
I would cut the growing tip, as they do get very tall, 5ft to 6ft.
I never got round to tasting them, as they take a very long time to flower and mine died of the cold as I didn't keep them indoors due to lack of space.
As yours is quite tall already you should get some this year if it's sunny.
It used to hold the World's hottest record before the Dorset Naga and Bhut Jolokia came along.
I think it was 300,000 scoville units, whereas Bhut Jolokia is 1,000,000+.