The same happened to me and to a lot of people, you are not the only one.
The best(and only) option is to patiently wait for the next update which will possibly fix the stability issues, once the update is out, it can be found on the itch.io page and it will also be announced on the discord server.
(I recommend that you always download it on the official itch.io page, do not trust unknown/unofficial sources claiming to have a new version of gacha nebula)