Call Poison Control if you're in the U.S. 1-800-222-1222.
Not all discrimination is illegal. What it comes down to is that a potential employer can decline to hire someone and they don't have to give a reason at all. They can decide they're not going to hire the perfect-on-paper candidate because of a personality clash if they want to or because a less qualified candidate is friendlier, more outgoing, and is prettier.
They can even decline to hire you if they find out you have children and they make assumptions based on that unless they asked you straight out during an interview. They're not allowed to ask if you're married, single, a mother, disabled, whatever. Nothing private. They CAN ask, "Is there anything that would restrict you from doing the job duties listed in the job description? Is there anything that would keep you from attending work on a daily basis or arriving on time?" All you would have to give are yes or no answers.
When I worked in retail as a manager, I had to interview a friend of mine for seasonal work. The problem was she was 8 months pregnant. It was obvious. I had to tell her outside of my workplace before she filled out the application (she told me she was going to do it) that she needed to keep personal details about herself off of the application and her resume. That she needed to present her best skills , etc. I gave her the job description, most of which she could do 8 months pregnant IN ANY OTHER RETAILER. She would be required to stand for 8 hour shifts, possibly longer, not counting a 45 minute break. She would be required to carry heavy shipments of music boxes. She would be required to climb 12 foot ladders carrying several boxes at a time up and down those ladders to put away shipments and to serve customers.
When it came time for me to ask her if she would be able to perform all of the duties in the job description and she said "no" to three of the required job duties (cashiering and customer service were secondary) I couldn't hire her. I had to make sure I didn't ask her why. Of course we both knew why, but it was a matter of safety for her and the baby, and liability for the store.
When I found out I was pregnant, I had to find another job because I didn't feel comfortable climbing ladders and I could no longer lift heavy shipments. It sucked, but I knew the job requirements.
Anyway, obviously a different situation than yours, but I see no reason to hide the fact that you have children on your Facebook. Tighten up your security and if there are any embarrassing photos of you out there, delete them from your albums and untag yourself from friends' albums that have embarrassing photos. I personally set up a business profile since my personal profile has super-tight security. They know I have FB at work, and that one is private and one is for work and other business-related things.