Hey there, Kikikora! Starting with the short answer: Yeah, as a small time comic creator myself, it can get a bit lonely from time to time. But thanks to the few friends who have been supporting me for years, the size of my readership doesn't really bothered me as much as it used to.
Time to addresss those bullet ponits!
1) No one to discuss my comic with in real life (my partner is very against BL)
Sorry to hear that your partner doesn't like the genre you work in, but I hope they still support you in making comics. Best way to find folks to talk comics with you in real life is to open up about making comics with people! Take that one with a grain of salt though, since I still have trouble doing that myself 
2) Small readership - not many feedbacks from readers
Been here, still here, but the easiest way to turn this into a positive is to cherish that small readership. Small authors kind of have it good, in a way, imo, when your readers do pop in and comment, you can respond to all of them without getting too bogged down. Make a habit of telling your readers how much you appreciate that they follow your work, and respond to them whenever you can!
3) Only receive comments within first 2 days of posting, then comment section remain died until the next upload
I think this one is a small case of the "build it and they will come" mentality in smaller creators. I've been stuck in this mindset for a long time before deciding to drop it and sticking up for my passion project.
Understand that it's a very rare and very lucky comic that draws attention without doing much at all. The internet is a big, b i g, place filled with content, and the only way to stand out in all of it is to "promote, promote, promote!" Your reader base may be out there, waiting for a story exactly like yours, but they can't find it if you don't promote and put it out there
Sorry for the long-winded spiel, but I hope this and everyone's responses help cheer you up in some way. You can do it, Kiki! The key to success is being so stubbornly in love with your work that you want to share it with everyone. Find that fire, and your readership size won't bother you! ....Well, as much