Hi, Dia,
I found that my daughter sleeps better and longer with a full belly. Once I started feeding her cereal and solids, she was full and slept better and longer, and still sleeps better today at 14 months when she is full when she goes to sleep, and drinks some warm milk. Since you are still only breatsfeeding, just try to make sure she is full right before her nap.
Instead of always picking her up, I will sometimes rub her back and lean over her crib until she gets back to sleep. Music works sometimes too; I play the same CD so she is used to it (Baby Classics Mozart and Bethoven).
My husband plays with her until she is so tired all she can do is nap, and that helps. When she was that young, she liked to kick so he would play box with her feet with the palm of his hands while she kicked them. Now he lets her play and chases her while she tries to get away.
My daughter does not have any medical issues at all, so after the first month, I felt comfortable enough to let her sleep on her stomach where she was most comfortable (and she would sleep longer) and would just check on her very regularly to make sure her nose was not down or in anything where she couldn't breath freely. And I would gently rub her back to make sure she was breathing OK, but not enough to waker her up. I also pray over her daily that God would spare her life and continue to keep her healthy, among many other things; my prayers are always answered where she is concerned, and then some. I also use cover on her because I figure if I get a chill when I nap at times and want something at least over the bottom half of my body, that she may too. No one can sleep in an uncomfortable situation.
The best advice I can give anyone, is to follow your gut insticts and treat your child the way you would want to be treated. That is Your child so your first thought (God's whisper talking to you) lets you know what to do for her. If you are not comfortable doing something or not doing something, regardless to what someone else has to say, pray and follow God's voice in your gut. I have always done that with my daughter, even when I was pregnant, and it has worked out. For a lot of things I am thankful I followed my gut instead of doing what someone else thought was best or what they say "has always been done this way". Times change and every person is different. I know I don't sleep well when I'm hungry or cold or too hot or my feet are cold, so why should be any different just because she is a baby? She is still human. Try some things out that you know help you sleep better at night and see if it helps her as well.
Good luck, and God bless. May you each have Perfect Peace and Sweet Sleep.