Found out today I'm expecting (4 weeks gone) - awful boyfriend situation - previous miscarriage

[oceanchild93]

I found out today I'm pregnant. I'm 5 days late so figured I'd do a test. VERY faint line - but the second line was there nonetheless. According to the pregnancy calculator I am 4 weeks gone and the baby's due date is 08/02/17. I have some concerns; Me and my BF have been fighting (we live together. I'm 23 and he's 29) so I've come back to my mums house for a few days to let things cool off. We have been together for a year and things were amazing up until recently. He was violent with me on one occasion a couple of weeks back. I said I'd forgive him if he got help (anger management or counselling) which he is doing and I've seen fantastic progression in him. I told him I was pregnant today and he was really supportive (he already has two kids (2 and 9) to previous relationships and we have them a couple of times a week). He hugged me and said we'd get through this. Am I doing the right thing??? My heart is telling me to go through with the pregnancy even though the situation is bad right now. I had a M/C to a previous partner nearly 3 years ago and I'm terrified it will happen again. I have period like cramps which are quite bad. Is this normal? Also I have sore nipples and I'm feeling a bit tired but apart from that I have no other symptoms? Also I drank and smoked a lot at weekend. I feel so guilty :( but I didn't know I was pregnant! I'm only a social smoker anyway so It's easy to completely stop.
I've had a folic acid vitamin and also some vitamin C. Now I'm waiting for my first apt with midwife.
Any advice or similar stories which can lift my spirits up will me much appreciated... Thank you :(