What did you do when someone else (or another team) launched a very similar platform to the one you were building?
Feel free to get emotional, philosophical, factual, anything! Situation is hypothetical so can be that the team launched before you or vice versa.
At first I laughed, then went "wtf", then felt better because we each had different goals in mind. It was in 2016 when Telegram launched Telegra.ph, and #writeas had already been out for almost 2 years.
After I saw the launch, I actually posted Write.as to HN for the first time, and the next day it was surprisingly on the front page of PH. It didn't do as well as Telegra.ph, and I had to answer questions about how the two platforms were different now, but the PH launch sent my own product in a new (more upward) trajectory.
Overall, once I got over that initial worry of having to compete (something I never worried about before), I focused again on my own goals and then kept going. It's good when many options exist in the marketplace, whether you're making the products or consuming them.