Big fat positive!!

So Friday I went in for blood work and they called and said that my pregnancy test was positive. They told me my hcg was 42. Well instead of being excited I flipped out because last time when I had the miscarriage it was 37. So I was excited and scared at the same time. I would not be able to handle another let down like the last time. I asked the nurse if that number was ok because the last time they tested me they said they wanted it to be 100. She said she saw no reason to worry as long at my progesterone was good and they would call me back with those results on Sat. At first I was angry they had to call back and didn't already have those results but in the end I will be glad she did have to call back.
Saturday the nurse called with my progesterone results and they were good. I asked her about the hcg of 42 and said I was concerned about it being low. She said well that last time we tested you at 4 weeks and it should have been 100 but this time we tested you at 3 wks 5 days so 42 is a good number. She also informed me that I needed to come in on Tues for more blood work to check my levels and the Dr decided because of previous test that he wants me to do heparin therapy for the first trimester.
Today, Tuesday I went in for more blood work and to learn how to load the syringe and give myself the heparin shot. I am to give myself the shot 2 times a day 12 hrs apart starting tonight. Nervous about it being a blood thinner but it will be worth whatever I have to do to keep this pregnancy going. I also had to wait till this afternoon to see if the number 42 had tripled. This would let me know if the pregnancy is going well. Well the nurse called and told me the number was 282. I am so relieved and happy.
Part of me feels I want to be cautious and guarded, but the other part of me is so excited I can't help myself. I just pray that everything continues on a good track and by this time next year I will have a little one in my arms.