We are a travel channel and we upload once a week so we don't burnout of content to post. Also it depends on your audience too! If views on your channel is quiet you may need to post more frequently :)
We have about 167 subscribers at the moment and our views vary on our channel. We get some videos that pop and get really good views then some don't. YouTube is random but I promise you'll get there :)
We've had this happen quite a few times on and off lately. We get up to our next goal then go down a few. So we just try and focus on enjoying to create our videos instead. It will happen over time it's a big platform now compared to previously!