I don't have any advice other than to say you are not alone!!
I have a 5 month old that won't nap during the day ever; at least not any sort of schedule. I am lucky if she gets an hour in the whole day and EVERY single day it is different times. And even then the only place she will nap is in the swing.
I have put her in her room and done the whole cry it out thing but like your little one gets worked up so much that I think what is the point...
Now I will say she does sleep threw the night for me most part so I at least have that going for me. But we haven't hit teething yet! Ugh.... so seeing how she is already bad at it during the day makes me think I have some harsh nights ahead of me when she does start to get those teeth.
I guess I just wanted to let you know that what moms will tell you and what is reality, sometimes aren't the same. The fact that all your friends kids are on such perfect schedules seem fishy, but don't let what they are doing make you feel like you aren't doing something right. Some kids just aren't good sleepers. I wasn't growing up at all, so I guess I am getting paid back :)
The best advice I was given by an older mom with grown kids was that once she let go of the idea that her kids had to be on some schedule or that they HAD to nap, her life changed and she became a better mom. She just let all the expectations go and just rolled with it.
That is the approach I am taking. My little one doesn't nap during the day, so I tell myself "so what". I leave the house when I need to and do what I can. Yah she has sleepy meltdowns here and there, but that too I just deal with.
One thing I will say is that perhaps trying to get her down earlier at night. I know that sounds crazy, but back when ours wasn't sleeping at night either we put her down one night at 7 for some reason and she passed out. Then stayed asleep all night. So we kinda just kept up the routine. We had been putting her down at 830 or so and by then she was just passed being tired and now was fighting us. So maybe try that??
I wish you luck and perhaps you will get some good advice from some moms, but hang in there and know that not all babies are perfect little sleepers and there are other VERY tired moms out there feeling the pain with you :)
ps... on the stuffy nose thing. My little one has had one since birth and her docs as well tell me it is nothing!? I was planning on seeing a whole new group of doctors because this just doesn't seem right to me. But now I see that you have been told the same thing.. hum... I wish us both good luck.