You are not clear about you menstruation
. What was the expected date, how long you are missing the period and were you regular in your periods previously are important questions. Anyhow pregnancy
if you suspect, rule it out by doing a pregnancy test.
You are c/o pain in the left side of abdomen ascending to the ribs, right sided headache, dizziness
spinal pain and heaviness in breast . Some of the complaints may be associated with pregnancy. If pregnancy is ruled out, I would suggest investigations. USG of abdomen, motion examination, urine analysis and if necessary urine culture and sensitivity. Treatment as per investigation followed by diagnosis.