I agree ^^ calm down tell your ex n take a test as soon as you can and from there you both need to talk about it because even though you two are not together the thing is that theres a life in you(if you are) and it took two to make. So his decision counts.
Take a deep breath, go to the store, and get yourself a test. Check, and if it's positive, make an appointment with your doctor right away, (because of the implant). If you are pregnant, it would be considered proper to tell your ex that you are pregnant, and what you plan to do. I would advise you either keep the little one, or go through with the pregnancy but give the little one up for adoption. Plenty of loving families would love a child, and cannot have one.
If it's negative, talk to your doctor about the pains you are having, and have them try to figure out what is going on.
calm down. dont stress until you take a test and got to the doctor.