Clomid and one fallopian tube?

This is my first cycle of Clomid 50mg and we are trying for our second baby. I had no problems getting pregnant with our 1st child and when we started trying again for our 2nd child (18 months ago) I fell pregnant pretty quickly but found out it was ectopic and had to have surgery to remove it. My right fallopian was also removed. It was a heartbreaking experience and something I don't ever want to go through again. Anyway, since my surgery my periods have been very irregular and very hard to predict so after 12 months of trying and getting nowhere my gyno has prescribed Clomid. I had my left tube checked and I've been told that it's open and free from scarring and blockages. What are the chances that I'll conceive with one tube and Clomid? I'm only allowed to take it for 6 cycles so does that mean (because I only have one tube) that I only have 3 chances of getting pregnant? I'm really worried that it isn't going to work and that we are going to be told to take the IVF route which we just can't afford. Is there anyone here who has gotten pregnant with one fallopian tube or knows someone who has? Or anyone who has gotten pregnant on Clomid and have any tips/ advice for me? I really want to make this happen and give my son the brother or sister he deserves. Thank you in advance x