Waiting for baby number 2

As we get closer to Addilyn turning two, I'm struggling more with the want for another baby, which brings on a whole realm of emotions.  For the most part I've been able to push them aside and feel completely content with where we are now, but as we get closer to Addilyn turning two I find myself thinking about it more often.  We've said for a long time that once she's two we'll talk seriously about a plan, whether that be fertility treatments or adoption and to be honest both scare me.  
There's been a handful of times this last month that I've thought of our lost babies through our fertility treatments.  I know there are so many women who have miscarriages and this is a common thing, but it is still hard and sad.  I know we have four babies in heaven that we never got to meet.  The idea of going through fertility treatments, knowing there are high possibilities to endure more losses is really hard.  There is so much that is not black and white when it comes to what I feel like are the best choices regarding fertility treatments and I struggle with this a lot.  I know without a doubt that God gave us Addilyn through IVF and it was His perfect plan.  But there are times I think about the fact that we had to lose four embryos in order to get Addilyn and I don't want to do that again.  We agonized over decisions, like how many eggs to fertilize because we didn't want a lot left over but didn't want to end up without any quality ones to use.  I know that ultimately God was in control of every decision we made along the way, but they were decisions that took up a lot of time, energy and prayer.  This unappealing part of the fertility treatments is almost as big as the physical and financial toll, which are both huge reasons I'm afraid to do it again.  
I think there was a part of me that thought I was going to be one of those women that go through fertility treatments and then gets pregnant easily on their own after having a baby.  Chris and I have never done anything to prevent getting pregnant since Addilyn has been born, and while I shouldn't be surprised, I'm disappointed I haven't been one of those woman.  I still have hope that it could happen, but the longer it goes the less I feel like that's a possibility.  
Today I saw two different pregnancy announcements (for baby number two) and I cried.  The day before I got my period and thought there was a chance, although so small, that I may be pregnant this month.  I felt sad and disappointed.  I think I've felt that since we already have a baby, I shouldn't be sad about not having another one.  Like it's greedy and unappreciative of what we do have.  But I think that there is a line between acknowledge your desires, letting yourself be sad, and to be content where you are.  
For a long time I felt like infertility defined who I was.  It was something that was on my mind all the time and I had to work hard to not let it take over my life.  I know that it is so different now that we have Addilyn, but it's a desire to have a baby nonetheless and I'm afraid to go through all those feelings again.  The jealousy of other pregnancies, disappointment of another month not being pregnant, and then more so the unknown and uncertainty of infertility or adoption.  
I remind myself that God taught me so much through our infertility until we got pregnant with Addilyn.  I would be a completely different person had I not gone through those struggles.  And I know whatever our journey looks like to expanding our family, God is going to do the same.  That it's okay to be sad and okay to acknowledge the desire for another baby.  But to continue to pursue contentment and be thankful for this exact place where God has us.