Based from the information provided it seems as you are having "PELVIC INFECTION".
Mostly it occurs after the menses as the immunity is bit weak during the periods and the use of "TAMPONS" has caused such issues, commonly staphylococcus
bacteria is culprit of such shock
like symptoms where the bacterial toxins are spread in to blood to the constant contact of tampons to body parts.
Please rest assured the symptoms you mention are " NOT from pregnancy"
1) Consult OB/GYN. as soon as possible
2) Get your self checked and they will do some blood work and prescribe some antibiotics to get you back on track.
3) Please do not TAMPONS and in case of SANITARY PADS do not keep them LONGER THEN then intended to do so.
Hope it helps.
Dr. JAY PATEL