There are many things to fix, but hey it's your first grow. at least you got something to smoke lol
i agree with others, need more light. the reason for saying this is, look how much the plant stretched, with enough light the plant with grow normally and not so tall.
this will also increase the strength of the branches allowing them to hold the buds up next time.
you can buy yoyo's to hold up buds, but only people growing buds the size of a 2-litre bottle use yoyo's lol. you just need a stronger light.
genetics also play a part, it could be bad genes. try good seeds from reputable breeders next.
also, increase nutes given. this will strengthen the structure allowing for stronger plants, and larger yields.
some recommendations for light are Spider Farmer, Mars Hydro, or Growlightscience.. they all make good lights.
nutes i use is called Floraflex, they have a product called bulky b.... bulky b makes it stronger to hold buds better, I suggest running the entire full tilt line, if not at least buy bulky b.
seeds and breeders that are good are, ETHOS genetics for photoperiods and fast buds or Mephisto for autoflowers..
please select me as the answer as I'm trying to win Grower of the month award your support would be truly appreciated growmie