you're not supposed to sleep with your contacts on. I've had mine for years now so.. I don't really wanna imagine the result of that if I did it

the contacts are generally good to make it through the day but at night, idk if you noticed but your vision is probably weaker. if you have them on all day, at night your eyes are weaker and your vision is less accurate than before that. for this, you could either get those drops to get your eyes wet, idk how but I think those drops are supposed to rest your eyes too somehow, or better yet if you ask me, take them off and put glasses on. by no means, don't go on with keeping them on, at night your eyes need to rest and with your contacts that's difficult. if you kept them on all night and tried to take them off when you wake up, you'd probably notice they are dry as hell. your eyes shouldn't get 'dehydrated' like that man, take them off during sleeping

as for the infection, the red is normal (normal as in, simply reddish from being tired and wearing your contacts for a long time, not like fully red in it

), my eyes are red as hell after wearing contacts for many hours. you'd probably notice an eye infection though not just by the color but feeling irritated in your eye. maybe it would sting, hurt, bug you ALL the time, notice somehing weird about your eye. if you're irritated in any way constantly , you should get a simple check up just to be sure, but an infection would be obvious really