Hi! I'm also the mom of a 3 month old. I was having problems with my lo only taking 30-45 minute naps as well. I bought Tracy's newest book the other day and it really helped. When he was napping on Saturday, he woke up after only 30 minutes. I had the monitor on, so I could hear him getting ready to crank up. Instead of him getting into full blown cries, I went in to check. It was funny because when I got in there, he looked up at me and gave me the sweetest smile like he was finished napping. However, having just read that he should be napping at least 1-1.5 hours, I shushed, pat and put his paci back in. I could see his little eyes were indeed still heavy. After about 5 minutes he went back to sleep for another 45! This happened again for his second nap of the day and even in the middle of the night last night.
I was just sure he was getting plenty of sleep when he looked up at me smiling and cooing, but sure enough, what was in the book worked!!
As for the nursing thing, I still have problems with that!! He does eat every 3 hours and has a dreamfeed, but he still pinches lots when he eats!