My daughter was the same way from birth. I know it is so hard, and you are so tired and just need her to nap for a bit during the day. I spoke with our pediatrician about this countless times, and his advice was always, "If she sleeps well at night, don't complain. Some kids take long naps and some don't." So, when I would get frustrated I would just remember that at least I was getting a good night's sleep, as was our daughter.
Also, our daughter gave up napping, but then went back to napping and occasionally still takes a long nap, even at age 3.5.
My advice would be:
1) Stick to routine. A 45 minute nap is better than nothing. Your daughter is just interested in doing other things.
2) If she ever wants to give up a nap, insist on "quiet time". I started this when my daughter gave up her nap after age 2. I firmly believe she needed down time, and even if she didn't want to sleep, she had to stay in her crib for a while. I would put books in there so she could look through them. I also believe this has helped her go back to napping, which she did shortly before after she turned 3.
3) Be thankful she sleeps at night. This carried me through many an exhausted day. Also remember: kids who take short naps, usually go to bed earlier and sleep longer, which means more down time at night for you.
Best of luck and hang in there. Cherish these times, they go so quickly.