Should I tell my doctor?

I got a depo shot a year ago, but I went to the bathroom and it felt like there was a tampon in my vagina so I reached up and pulled out a fetus of about 3 months.. I was completely horrified, and I've been keeping it in a warm fish tank and putting apple juice and pedialyte inside. Please please help me, I don't know what to do.. I'm pretty sure it's alive and growing, it moves occasionally and also has Its placenta. I don't want to tell the doctor because it sounds horrible but I want to keep this poor baby alive. Please help. Thank you.