postpartum 8 weeks...

Last night I woke up around 2am to make a bottle for my son. When all of a sudden I felt a weird stomach ache then get so nauseas. I went to the bathroom I felt dizzy and I started shaking uncontrollably and very cold with a fast heartbeat. I lied down and fell asleep and woke up feeling better. Could it have been an anxiety attack? I don't sleep much either I'm exhausted. I'm so sleepy now I also bled from Friday- Monday again. Please anyone else going through the same? I went to the ER Saturday and said the bleeding was my period. So I don't know.