[ Pregnancy ] Open Question : Possibly Pregnant or Confusing Menses??..With these symptoms could I certainly be pregnant?

There are hundreds of "could I be pregnant" questions that I've searched over for endless hours, but I suppose I'll break down & post my own question since every individual is unique. I'm wondering if I could possibly be pregnant. Here's a bit of background history below: During the month of June I had a menstrual cycle twice-one the beginning of June & one towards the end of June. In between those times, I did have sex. During the month of July, I had (what I think) another menstrual cycle towards the end of July. During the beginning & middle of July I engaged in more sexual activity. During August...NOTHING! & I'm not sure when I'm supposed to be due for another menstrual cycle because the month of June certainly threw me off since I had two menses in one monthl I'm guessing, due to hormonal changes or something I'm supposed to now menstruate at the end of every month now instead of the beginning which was what I was used to for so long. In addition to my confusing menses, I've been experiencing mild to moderate (only one incident of severe) cramping that has been occuring for about two weeks. The cramping is seemingly NONSTOP-all day, all night...I also feel pressure on my bladder, especially so when I have to urinate. I feel some relief after voiding but not much-the cramping is still lasts. The cramping also seems to feel worse @ night. Normally, I am completely aware of my pre-menstrual symptoms..I get the tender breasts, headache & slight cramping but only 2-3 days BEFORE i menstruate not weeks! Right now the cramping is still occuriing, however I do not have tender breasts, no headache, no feelings of nausea only the constant cramping and feeling of pressure on my bladder. About 2 days ago after using the restroom, I noticed a brownish-red color on my tissue. I thought it could be a sign that I was possibly spotting...??..I called a pregnancy hotline & the advisor says I could very well be pregnant & the bleeding that occured from what I assumed to be a menstrual cycle could very well have been implantation bleeding & not a menstrual cyle. Any input & advice is VERY WELL APPRECIATED & if i could give more thant 10 points to the best answer i would. I am very nervous, anxious, eager & a bit excited...I just want to know because this is all very scary to me & I have just been accepted into a nursing program which is very demanding in itself & being pregnant during nursing school will indeed be seriously demanding.. OH, I live in a small/very rural town where there are more cows than ppl...I would have taken a pregnancy test ages ago but of course, our one little country store ran out! ugh! I scheduled an appointment to see my doc but I seriously can't wait!! Sorry for the long post but appreciate any insight! Thank YOU!!