How to think positively

Cherry🍒 • wife and momma enjoying it all
Hey ladies! I had a iud (mirena) for about 8 years.(I'm 29 now). Had iud removed march 3 2015. Got pregnant in march sometime. Had a mc 5 days ago at 5weeks or so :( 
I don't know why I had a mc. Maybe because I just had iud removed or something. But my doc says that these things just happen.  We didn't exactly plan on conceiving on the first month. But bam it happened. 
Now I'm struggling with negative thoughts and fears about future pregnancies.  How can I get past these thoughts? And advice?  How did Some of you ladies get past the fear?