Feeling a bit frustrated (Clomid/Letrozole Post)

I apologize to everyone if this sounds a bit like I'm crying and complaining. I just really need to vent a bit.

I feel a bit conflicted right now from reading through other forums regarding experiences with Letrozole or Clomid, and I want to see if others could give their thoughts on what may or may not have worked for them.

This is my first medicated cycle with Clomid and progesterone, and I'm a bit nervous that this will be a failed cycle. My fertility clinic mentioned we would use Clomid for 3 cycles and then go straight into IUI or IVF if the medication with TI fails. I've been coming across a decent number of subs on different forums, recent and a couple of years old, about how Letrozole had been a success for some on their very first try, but I haven't seen much about Clomid successes.

I'm pretty much stuck with a diagnosis of unexplained and secondary infertility, which might be contributing to my frustrations. My blood work is good, tubes are open and clear, and my partner's semen analysis is fine. The only issue I had was some scar tissue in my upper right uterine cavity, which was removed last month, and then my uterine cavity was marked as clear and normal. This medicated cycle started right after my hysteroscopy.

I might be getting in over my head a little, but I'm wondering if I should advocate for myself on trying Letrozole for this next cycle if Clomid doesn't work.