I was like this for about a year. I just didn't want to talk to anyone, or cook/wash up in front of them - I preferred being alone hugely.
When it gets in the way of other things you want to do though, like eat proper sensible meals at times convenient for you and keep a proper sleep schedule, you have to eventually deal with facing what you don't want to. I think with time you will grow more comfortable. After that first year, I started appearing in the kitchen more to be healthier. I've now lived here 4 years and I still stick to myself but I'm a friendly enough presence, sometimes even having more sociable bouts of hanging out. I use the kitchen/bathrooms whenever I want, don't mind or avoid the few minutes of chat that often happen and don't fear or worry about staying mostly silent either when I feel like it. Admittedly, even now I keep some 'emergency' supplies of convenient food in the room for when the kitchen is particularly jammed and I am feeling particularly unsociable hah.
Everyone seems to accept that I'm just quiet and reserved as a person, I don't think anyone disliked me. I even made good friends with a couple of the housemates despite my nature because they're really cool people. I would hang out or go out with them every couple of months (that's what I tend to be like socially, never suffocating ahah) and still do now that they've moved out. Even while they lived here, I never came into the kitchen expressly to socialise outside arranged house events/parties (some of which I'd decline to attend too) and they've remained comfortable friends so I honestly don't think anyone cares how you decide to spend your time; even if that means only rarely talking to them. They gave me the nickname 'Sadako' for mysteriously being able to enter and leave rooms silently.
As long as you seem nice enough when they do see you, everyone will just assume you are nice enough. That's my sense of it anyway. When I have been more involved with the housemates, more aware of the gossip amongst them (I'm in a house with 14 people currently), I noticed they all talk when a new housemate moves in to say 'I met the new guy/girl briefly, said hello, they seemed nice' then if they happen to be a quiet person (currently there is one guy in the house who is super reclusive like you are now and I was in my first year) the housemates will comment 'haven't seen the new guy/girl again, have you?', 'nope me neither', 'must like to keep to themselves'. Then that's all. People just accept it. So don't worry about that or let it be an obstacle to you pushing yourself into using the house more healthily. No one cares, honestly.