Hi. Same thing happened to me last wk, 9 wk into flowerin tho. I guess the weight from buds pulled it down. Mine split bout 1 1/2 inchs down stem tho. I jus taped a splint to it and at top where i couldnt get it completly together was exposed, so i put a small piece of rockwool over it that i could wet to try and protect it. Seems to have worked so far, cant tell any difference.
Hope it works out for ya. I know what its like to lose plants, as everybody does i guess. GL