So my situation goes like this : I happened to land upon a significant discovery in my lab In a very field very hot right now. My  bosses are awesome and we send our findings to a ~20 impact factor journal as a rapid communication. Journal review comes back 3 weeks back, reviews are favorable. 2 of 3 reviewers just commended work and did not  ask anything  and third one asked to show extra proof.  I do some extra experiments for revision of article and we send it back this week. I think we satisfactory answered all reviewers questions. 

The day we send it back we hear of  a similar paper published in a  different but very famous  journal by a well known scientist of that field. While his work is much deeper  than our rapid communication in one cancer , ours is more broad and applicable to more cancers than his work (that’s why rapid communication as we had hoped we could build upon the work) We also show a very different mechanism that his lab  didn’t. It’s a question of two different labs landing upon a similar  discovery simultaneously. Now my paper is still under review by that top journal. How will his publication this week affect my chances of getting accepted by this journal? 
Time line is this: 

*my article submission: Feb 20 2018
My revision submission : Mar20 2018*

**Similar paper submitted : October 2017
Similar paper gets accepted : Feb 18 2018
Similar paper gets published: Mar 20 2018**

 I am pretty sure if he hadn’t published,  our paper would have very likely got accepted because it’s a big discovery. But now that he has, I am feeling all the jitters, nightmares etc. it’s literally  two years of my day and night hard work that has gone in this work. Just super concerned.  
I am not a PhD, just an  MD. So I am unaware of how these situations are handled in biomedical scientific publishing.