Need advice!

So I'm 34 weeks having a few complications that aren't serious, but have earned me moderated bed rest. My husband is really worried and my whole family and anyone I seem to come across thinks I'm at least 2 weeks farther along than what my midwife thinks. Mind you, I haven't had an ultrasound since December 15th and my doctor said I won't be having another. So I have no idea what my baby is weighing or how big he is. I am a first-time mom and was wondering if any of you experienced moms could tell me what signs to look for when you start labor or when to start suspecting you're in labor. I just really want to be prepared and ease my husbands worries.