Why do we settle?

So, around the last time I posted, I had just started talking to a guy.  In April we started dating and I let myself get all wrapped up in him, more so than I had ever done before.  I loved him completely and I gave him all of my heart, my time and my energy, but I didn't neccesarily get it all in return.  I was happy just spending time with him and his 2 precious little girls.  There were many times that I was unhappy, but then there were those times when things were so good.  I knew that he had many issues from his ex, but I always hoped that I would be able to get his whole heart.  After 7 months, all our issues came to a head and he dumped me.  Through the pain, I realized that all of the issues he was using for the breakup were not really our issues, but the issues he brought in with him from his ex.  The more I thought about our time together, the more I realized that honestly, as much as I love him (and I use the present tense because I do still love him) that we are just not meant to be in a romantic relationship together.  He could not give me the things I wanted and needed. We both enjoyed each other's company when we were dating and we are still friends, even though it still hurts on occasion when I think about how much I love him. I guess this is just a case of the heart wanting what the head knows is wrong.  So now I have the dilemma, what do I want now.  I know I need to work on me, but I hate being alone! Everything in my life went wrong all at once- more than just the relationship.  My son has behavioral problems, my health has been bad, I failed a class, and I got in trouble at work.  And as if things couldn't be worse, it all happened Thanksgiving weekend.  I have never felt this down before, I have always been able to see the silver lining, but not now.  I can't seem to get into the Christmas spirit and I am having a hard time being me.  I hate taking drugs, but I might just have to break down and take the anti-depressants the doctor gave me.  Sigh.....why do we do what we do?  Why do we settle? Why isn't love enough?  So many questions and no answers.