Grown on roof/balcony. Random seed.

I grew her on my roof/balcony. She was a pleasure to grow especially for my 1st time. I found a seed in a bag of weed, so I thought I'd plant it last spring. She grew very well considering the uk weather conditions we did have last year. She was a very sturdy breed, withstood bug attacks she never got diseases so a very robust plant. She even took a beating from some of the storms we had last year. I only fed her water for most of her life and fed her tomatorite once she flowered. Overall she was a dream to grow. Once i had harvested her she weighed a nice 21ozs wet. Once cured she weighed 5.8ozs. I thought wow absolutely loving the results at this moment of time. So I thought I'd crack open a nice well deserved bud. Put into the grinder and unfortunately it was all seeds!!! :( :( I was gutted! My conclusion of what happened to her is that i was taking her in every night for her 12/12 cycle and putting her into my wardrobe (she only just fit in) so I believe I stressed her out enough doing soo and she seeded :( if anyone knows if this is properly the case or knows why she could had seeded please let me know!! Thanks for reading! Stay safe!