Abnormal period beginning to worry :(

I came to this forum asking for any advice that you might give me. I will get checked with a gynecologist soon, but I wanted some insight from women who have gone through what I've gone through to see what it might be. This is my current situation:

I am a 22 year old woman. I have become sexually active since Dec 2011 with my boyfriend. I've had sex before but nothing ever has happened that has made me worry until now. I am fairly irregular. I don't usually know what day I'm getting my period every month since it usually varies, but I do know that I get my period every month. My last period was in Dec 17 of 2011. I went the month of Jan and Feb without a period. At first I thought I was just being abnormal since I sometimes missed my period but started feeling worried when I went 2 months without it. I was cramping slightly and had breakouts. Typical PMS symptoms. 

Sometime during Feb, I took several pregnancy tests to see if maybe I was pregnant, which at the time I highly doubted it since my boyfriend and I always have protected sex (condom) and I ask him to pull out before he comes even though he wears a condom. All the tests came out negative, but I still wasn't getting my period. I asked my boyfriend to take me to get a blood test to check if I really wasn't pregnant. The results showed negative. 

After the results, I figured I probably really wasn't pregnant. I waited more days to see if I maybe got my period and I didn't see anything until like maybe 2 weeks ago when I noticed that I was bleeding lightly. I thought it probably was my period. Well, now it turns out that i haven't stopped bleeding since 2 weeks ago. It is not regular moderate flow like my periods usually are. This is very light; sometimes it's brown like old blood, sometimes red and I've noticed some blood clots. I find myself wearing a tampon every day to prevent me getting dirty. I have also noticed that I feel pain during sex, which didn't happen before. At this point, I kind of feel worried that it might be cancer or cysts or something potentially life-threatening. I also fear that maybe it is a miscarriage. 

I have decided to go get checked as soon as I find a gynecologist since I don't have medical insurance. What do you guys think about this?? Any help/advice would be appreciated :)