Okay, four months have passed and NOW we actually DO have confirmed reinfection cases:
It still is in no way a reason to panic though, because:
There are over thirty million confirmed infections at the time of this writing, and just a dozen of confirmed reinfections. Statistically this is literally nothing.
The reason why these reinfections occurred is that there are three clades of COVID-19 ("Asian", "European" and "American"). The aforementioned dozen of people thought that they are "invincible" after surviving Covid, so they went traveling around the globe and contacted another clade (compared to what they had immunity from). So, unless you are traveling around the globe, your chances to get reinfected are even lower than 1 out of 3,000,000.
All these reinfections proceeded in extremely light forms and in some cases were discovered by pure accident, because the reinfected people didn't even know that they are reinfected (and it makes sense, considering that the immunity acquired from the first infection didn't go anywhere).
So, you can still rest easy on this front (so far).