Help!

I found out I was pregnant this Monday at 12 DPO. I couldn't believe when I saw the two lines on the test since my bf and i have been trying for 5 years. We had a miscarriage 2 years ago. I told my bf about the positive tests, we waited for Wednesday to see if I got my period. No period yet. I don't know how to feel I've done 3 pregnancy tests and more than 5 hcg tests and all positive and stillcan't believeit. I'm scared to get excited and feel happy and to have another miscarriage. I feel guilty for not feeling excited. I just don't know what's wrong with me.