Help please

I'm 33 weeks having excruciating back pain they gave me a steroid shot how long does it take to kick in an develop baby's lungs also I have the flu doctor said that could cause my contractions to be worse an make me feel dehydrated I go back at 35 weeks

:also the excruciating part has stopped its just crampy an achy an my preterm test came back negative which means no amniotic fluid leaking but if my pain gets worse I need to go in I just don't know what to look out for at this point they said I was dialed to 1.5 an if I was a 2 they would have kept me I'm still hurting but what do I watch for until I go back to the doctor can I have sex or no

There's more that one question in the post I need help not judgment I've had the flu for several days now I'm sure it's almost over an I have 2 weeks before I go back to the doctor I'm pretty sure I wont have the flu that long