Pregnant? Brown Spotting?

So I have been having unprotected sex for the past 9 months that my boyfriend and I have been going out. I’m not on the pill and he doesn’t like to use condoms.I got my period about a week early and it started out as some blood and I felt like puking that morning. I also had very bad cramps that day, to which I couldn’t get out of bed. But for this past week it has been off and on. Like I could go a day without a tampon then need one. But it hasn’t been blood. It’s been a light brown color that I occasionally experience at the end of my period. But it has been off and on with this old blood. And here and there there is a spot of red blood. My periods are always very heavy and maybe a slight brown color a day after my period has ended. Never this light nor on and off like this. Plus it is never always a light brown color the whole time throughout the week of my period. I passed out about a month ago. Ended up going to the emergency room and that damn doctor told me that it’s normal for teenagers to do that. I honestly don’t know anyone of my friends that has randomly passed out. I also was having pains throughout my stomach, under my ribs and moving to my sides. Which then moved to my back and in to my shoulder blades. The doctor blamed that on smoking. I’ve smoked for about 4 years now and I slowed down a lot. I have maybe one or two cigarettes a day and I have been gagging afterwards or my stomach gets very upset. Certain foods make me want to puke, but I haven’t but they really upset my stomach. My stomach is kind of hard. And I’m worried I may be pregnant? Can it be something more serious? Can some one help? Or relate to me and has answers.