People of all shapes and sizes attend clubs, so you should be fine.
Obviously some people gravitate towards certain venues which have a more relaxed attitude towards people of a larger shape.
Chamelons is probably the most relaxed in this regard which is probably a hike for you, but you can book a room there and stay over night.
La Chambre is a very relaxed and friendly club on a Saturday night, I wouldn't advise a Friday night for your first visit because it's more like a Benny Hill show (If you have a walk around you get a pack of not so attractive men following you about)but I suspect all the mixed nights are the same the world over.
Good luck and if turn up will probably have a chat.