Is it possible after a laparoscopy?!

January 4th I had a laparoscopy to remove endometriosis. It was confirmed that I did indeed have it. It was removed and I was good to go. My husband and u have been trying almost a year and a half to have a baby. Well I was due for my period last week (1 wk post surgery). I assumed my body was off because of stress. I had my post-op yesterday. My doctor reassured me that surgery can delay the cycle. Well, long story sorry I have not been feeling right. I took a test tonight and it said positive. But the doctor took blood and urine 2 weeks ago morning of surgery and it was negative. Is this true? Has anyone experienced this?