could I be pregnant?

Okay so, I have to give a backstory. I have been pregnant before and didn't know it because I had my periods, every month, on time and had no pregnancy symptoms. My periods were short and light, so just in case I took pregnancy tests and they came back negative. I even went to the doctor and got a birth control prescription and she did an exam and said everything was normal. I was pregnant and miscarried at 3 and a half months. I never went to the doctor, but believe it was a miscarriage (fetus was the size of my pinky).
I had a period in the end of June, on day 16 of my cycle I had sex and used a condom but the condom broke. I had a period in July, August and this past week in September. All very short and very light. My normal periods are 4-6 days with 3 days heavy one light and 2 days of spotting. These periods the last few months have been about 1-2 days of very light with 1-2 days of spotting. Also, it almost like a pink or brown discharge with a thin, clear, slimy coating. I have had cramping and bloating throughout my entire cycle, when normally I only have cramping the first day of my period and its not very bad, 2 ibuprofen and I'm good. Also have been very tired, but can't sleep. Have bad headaches and often feel dizzy when I move quickly. The other strange thing, I went to bed one night and woke up with my breasts a cup size larger, they feel heavy. I was just wondering what the likelihood of me being pregnant again with period and negative pregnacy test results. If so, does that mean it will happen every time I get pregnant? How am I supposed to know if I am pregnant if I have my periods, get negative test results and have hardly any pregnancy symptoms? Also, does that mean I will always miscarry and will I ever be able to carry a baby to term? If you could answer all my questions that would be great! Thanks!