IUD pregnancy?

So I'm 4 1/2mo pp. my husband and I started having sex about 3wks after baby and he always pulled out. My son was born April 18th and I had my Skyla IUD placed June 6th. Over the last three weeks I've had some hard core prego symptoms 😳 I had hyperemesis with my son but lately I've felt nauseated, chicken kind of makes me want to vomit, and my lower back.. What are my odds here? I'm considering getting a dollar store test just to shake my "fears".