I know how you feel, I had a Molly who decided to explore under a ball of Java Moss I had in the tank as I didn't want to stick it to anything for a while. It got stuck overnight and by the time I woke up she was dead We learn from our mistakes
Awww i'm so sorry to hear that, but has been said these things happen, i have just lost a female who got stuck behind the filter. Keep you chin up sugar.
As for the number of females, you should keep no less that 4 together