feeling like i've been getting fevers

Hi,
Welcome to ehealthforum,
Your symptoms (altered period, pink spotting, abdominal cramps, low back discomfort, increased body temperature) could be suggestive of possibility of pregnancy. Urine pregnancy test (UPT) kits are calibrated ones, so unless the hormone levels in urine reach a certain level, they do not show positive results (UPT should always be done on early morning first urine sample as the concentration of pregnancy hormone HCG is believed to be highest in this sample). They can also show false negative results. Blood/serum HCG level estimation is accurate. Wait and watch for your next period. If you suspect to be pregnant, look out for development of any other new symptoms suggestive of pregnancy. If periods do not start within 10 days of expected period dates and you continue to have (or develop new) symptoms suggestive of pregnancy, you should consider visiting your doctor/gynecologist at the earliest for further examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately). Take adequate rest. Drink plenty of water. Maintain healthy diet.
Take care.