I've been Muslim for almost 6 years now, and like others I don't feel entirely comfortable in the mosque. You will always be watched, scrutinised and judged to an extent alien to born Muslims.
I'm used to it now. I have as much right to use the mosque as any of God's creatures, and I do as I please there. If I still feel like a bit of an outsider, that's a reflection on other people rather than me. I attend mosque because I have an obligation to do so, and it does give me a spiritual boost. It's not perfect, but I've learned to live with it.
The only thing that really vexes me is the continue absence of English in many mosques. You can forgive the failings of individuals, but hope that those in charge would take the lead in making newcomers a bit more welcome.
There is no compulsion for you to assimilate; remember that not everything that other Muslims say / do / believe is correct or worthy of emulation. Do your own thing, and you will build friendships with those who have the manners to treat youy properly.
Hmmmm, you know, I was born a muslim, and to be honest in growing up, I don't really remember a time when anyone at the mosque differentiated between muslims i.e converts or non converts.
I think that sometimes when we make a change, it can be percieved in a variety of ways by others and we can also be sensitive to a certain degree in interpreting others reaction, behaviour and or actions when we are sensitised.
When I returned to England to live, I went to the mosque on a Friday and in the womens' area it was not hostile, it was not unfriendly, but it was not friendly either, this was not the same as the attitude or should I say warmth I learnd to associate with Islam and Jumat in Lagos which is where I grew up. Jumat in Lagos is a flambouyant affair, we put on our best clothes and go to hear the whutba, then go to hear the lecture before and after prayers.
My gran used to have to send us to get a good spot with the mats because the mosque would always be overcrowded and you would be outside for fresh air, it was like holidays where people scramble for a beach and sun spot. Sometimes we would be lined up into the main road and cause a traffic jam or the street would be closed. Imagine a family of nine or ten, you need two mats and if there was dirt you had to clear it then lay your mat.
Everyone smiled whether they knew you or not, everyone said hello. We particularly enjoyed being given your zakat by grandma and grandad then you would try to split it into smaller coins so everytime the collections box lady/man came past shaking it you could put money in. Once over, we got to stop and socialise a bit with friends who lived nearby and then you got treat money from adults at the mosque and then go to buy sweets to eat but we had to rush ahead of my gran so she would not catch us.
I gave up and started to either miss, skip or pray jumat using the telly, I was even told that women don't go mosque for jumat its not sunnah etc. I don't go here currently for logistical reasons, but I did pull up the courage to return to the mosque for eid prayers last year and since then I have continued.
At the mosque I go to, people are respectful, helpful, friendly and smile at you and greet you etc. But aside from that it is pretty much normal for people to simply greet and then ignore you, that is the way of the world now.
Having said all the above, I suppose what you should always bear in mind is that you do not go to the mosque for the people or for the atmosphere, you go there to worship Allah.
You will find that with time, just like the new student, people may begin to recognise you or remember you because of you not them, You must go in, and greet people with confidence, smile, show you are respectuful and ask questions aobut any thing you are not sure of like for wudu and so on.
It takes time to establish a relationship with people at the mosque after all you are a stranger to the people there just as they are to you.
You don't need to be friends, just be civil, you don't need the acceptance of the congregation, you need and already have that of Almighty Allah.
Familiarity can sometimes breed contempt, so... as much as one craves being warmly greeted and known and popularity with congregations, also understand that you may not like it if too much interest is given to your attendance and you may not want to share your personal life with the people at the mosque.
So in principle and to conclude, continue to go to the mosque, it empowers you to maintain good habits outside of congregation, it also gives you confidence in your daily life.
Stop completely noticing who said, did, or was at the mosque, instead go in, greet, find a spot, wait for adhan and pray, remain if you want time to meditate, remain if you want to simply be in a quiet place then finish and greet all you see, know or encounter and again, go home. It is as simple as that.
May almighty Allah strengthen your confidence in yourself, your ability to feel the peace and comfort of islam and grant you the grace to feel accepted by yourself first and then by others and strengthen your faith in Allah and his ability to guide, protect and support you. Amin.