Alamak, tension betul kan situation camni, 3cm bukaan tapi contractions tak strong lagi, memang scary especially masa tunggu-tunggu. A few of my mum friends went through similar situations, and honestly the waiting game is the hardest part; the good news is your doctor is being cautious for a reason since baby is still early at 35 weeks. I'd suggest keep track of the contractions closely (timing, intensity) dan contact the hospital straightaway if they become regular and stronger, or if ketuban pecah or anything feels different, jangan tunggu, just call lah. In the meantime try to rest, stay hydrated, and try to stay calm sebab stress pun boleh trigger false alarms; you're doing everything right by following doctor's advice to go home and wait for the real thing. Praying everything goes smoothly for you and baby!