Really messed up situation here, need some advice.?

OKAY...I have/had a friend with benefits. It was a mutal beneficial relationship with no strings. Well one time we must have not been all that careful because, wham bam I'm pregnant. I found out when the doc thought I was miscarring. I told my friend because there was a chance I wouldn't lose it, then the doc told me I did...(we're not even going to touch my emotional rollercoaster here), well, today I couldn't stop vomiting and so I went to the ER (it's Sunday, doc office not open), well guess what...I didn't lose it, the other doc was mistaken...now what? Do I tell him (although I did tell him I lost it) or do I sit tight, I'm not out of the woods yet, what? Some advice would be greatly appreciated. BTW was on an IUD when I became preggers, I decided to have it removed due to pregnancy, and there are a few other health issues...