Please any advice

I am 24 and have been trying to get pregnant. I have never had pregnancy scare or miscarriage before so for the longest time I thought I couldnt. I was seeing a doctor for pains but they never found anything. This month I was supposed to start on the 4th but I kinda expected to start on the 11th I have had an irregular period most of my life and recently I only bleed for 2 days. Well I started on the 9th and bleed normal but then i continued to lightly bleed. On the 17th I took a test and it came back positive. I went and saw a dr and they took blood and he said 80% I'm miscarrying but I could also be only a week along with how low my hormone levels are. I'm still bleeding lightly and I have been throwing up and my breasts are very tender and I think a little bigger than normal. Ontop of I am a smoker and I cant even smoke without upsetting my stomach. Any thoughts?