Baby sitting

So I baby sit a 2 year old and I watch my daughter. I’m 13 weeks pregnant and I don’t know how to tell Nicole that I can’t watch her daughter anymore. I’ve known her family forever because her brother was in my brother’s class. But anyway I’m due in March and I don’t think I can handle 2 toddlers plus a new born. Iv been told by my doctor I will have another c section. Plus we might be moving in that time and I have to finish planning my wedding.So I won’t be able to move around like I can now. I have been watch her daughter for about 4 months now and she always says how thankful she is for having me watch her daughter. So what do I do?