I Had My Periods On 28th Of March,I Srarted Feeling

I had my periods on 28th of march,I srarted feeling ill from 2nd of April I went to the hospital,I collect 6injections dats 2 daily for 3days.am expected to see my period on the 22nd\23rd of April and I haven't seen it I didn't also involve myself in any sexual activity but can I be pregnant????am also feeling pains like it wants to com but its not