Scared I have something serious!

Hi. I am a 24 year old female. I have been spotting between periods for awhile now, maybe 6 months or so. I have always had normal periods until I had my 3rd child. I had c-sections with all my children and my tubes tied with my last chld. I thought maybe it was because my tubes were tied now 19 months ago, but now I think it's something else. 3 months ago I was excersing and I gushed bright red blood all over! No pain until later that night. The pain and spotting lasted for about 1 week then ended until I had the most painful sex ever with my hubby and then the bleeding started up again. That was the worst it had been. I seem to bleed lightly after sex and when I think I am ovulating. Sometimes other times. A few other things that I have noticed are a large loss of hair when I wash and blow dry and acne! I never get zits and now I get 10 at a time!! Could hormones play a big part in this or could it be something serious?! Could it be stress? I have a 19 month old, 7 and 5 year old. I am a stay at home mom with my own small buisness. I do get stressed now and then when I don't get a brake for 2 months. Over all I feel great!
This worries me, I hope I don't have cancer!! Please email me you thoughts!! Stephanie