I haven't started my period yet, and I'm 18, and have bloody discharge...

So, I am 18 and still haven't started my period. My mother is concerned but still hasn't taken me to the doctors [or she tried once and they didn't accept our insurance]. On my college campus the doctor there tried running some tests -something with an ultrasound-, but through various circumstances I didn't take them, although they did draw my blood and I don't have a hormone imbalance.

Since I was about 12 or 13 I have had light vaginal discharge, it's gotten a tad bit heavier over the years and I used to be embarrassed but eventually I stopped paying it any mind. As of about a week ago, though, it has gotten very heavy, very sticky, and bloody. I thought it may have been my period but my urine was still clear of any blood. The discharge has also been brownish, though it doesn't care much of a smell, and yesterday it was only clear again, but this evening it went back to bloody splotches. 

I was taking antibiotics for a sinus infection and another drug similar to Claritin and this began the day after my antibiotics ran out, but I still took the Claritin one. Thinking it may have been a strange side effect I stopped taking them, but this hasn't stopped or changed at all.

I'm back home for summer break but I don't really want to bring it up to my mom, she'd either push it off as nothing or make a huge deal out of it. 

Any ideas as to what this is or how I may be able to treat it with household things [just not going to the store and buying Monistat or something of the sorts]. I am not much of a medications person, I don't like the idea of them and only take them if I have to. 

Oh, and I am about 5'5"-6", 127lbs and rather active. I don't work out everyday, but about 4 times a week I run a few miles and switch off between targeted weights, and I don't have any sort of physical disorders or mental ones that would effect this. I used to think I didn't start because I'm small and active, but it's getting to the point I'm actually slightly concerned. And, proudly, I am a virgin. I've never gone past a kiss, so it's nothing of the sexual sort. 

Thank you to anyone with any info on this! =]