My five pound 5-year-old Chihuahua ate one of my beyaz birth control pills! Please help!?

Okay, she hasn't eaten it yet, but I am afraid she will. This morning, I accidentally dropped it on the floor, but I don't know where. I've got it rounded to one place, but I am searching over and over it again and I simply can't find it. I am worried about my chihuahua, who I have in my room at the minute to keep from anything happening. I am so mad at myself! If she eats it, what will happen? She's five years old and a normal-sized Chihuahua--not a teacup in other words--and pretty small--rounding about 5-6 pounds at the most. She was just spayed about a little more than 2 weeks ago, so it makes me wonder if anything at all will happen. The birth control beyaz I take is the lowest dose. I have to take it because of an illness that I have. Also, I can't call anyone about it if it happens. We just moved and we haven't got our phone set up because the man refuses to come for some reason and I can't get any cell phone service where I am at. Thanks for any answer that will help! Also, I won't exactly know today if she eats it or perhaps tomorrow, so should I be looking out for any signs? Thanks again!