virginiad
i can totally relate to your feelings. i was so angry and frustrated and stressed for the first few months of my dd's life because i could not get anything to work for her naps. i felt like i was doing something wrong, becasue it sounded so easy in the book, but i wasn't able to make it work. and i was exhausted too (and i don't even have CFS!) what you are feeling is normal. not everyone can make thier child do exactly what they want, no matter how easy it looks on paper.
for me what really helped was letting go of my idea of how our day should go. of course, i still tried to guide my dd as much as i could, but had to realize she is not a robot and will not always do what i wanted. so just letting go of some of the control took a lot of stress off. i tried the best i could to get her on a routine and that's all i could do.
my dd couldn't stay awake for 2 hours at 4 months either. she was 6 months before she could stay awake that long. so don't feel bad if your baby can't stick with the times set out in the book yet. just do the best you can.
also, you say taht your dd shows tired signs shortly after waking up. in our experience, gianna would do that too, but she wasn't really tired. it seems like a lot of babies around 4-5 months of age will show tired signs at the "wrong" times. i learned that when gianna did this, she was just bored and needed a change of scenery.
as for the short naps, i really think that they will improve on their own. a good book to read is called "healthy sleep habits happy child" by marc weissbluth. he has a lot of research on infant sleep that you may find helpful.
i know this phase is SOOOO hard, but it will pass. just do the best you can and realize that is all you can do. it's ok if it's not perfect. it takes time to learn what your dd needs and how to meet those needs. if you have any questions, you can pm me. and check out the naps board if you haven't already. there is a lot of info in there on 45 min naps and how people work around them. good luck!