Does IUI Help To Conceive While Having Endometriosis?

hello iam Julie , am 28 years old and TTC. I have endometriosis, have has laproscopy done and was on zoladex for 6 months. Now my doc gave me medicines to ovulate (Letrozol) and asked to get IUI done. Do you think it is correct method?They also did HSG test and told me that only left tube is patent.I am wondering why after laproscopy only 1 tube is good. This time I have ovulated on left ovary, and I went for IUI. What are my chances of conceving? Is IUI waste of time for my condition?Thank you!