Hi everyone, my belly gets as hard as a rock in the evening and it loo…

Hi everyone, my belly gets as hard as a rock in the evening and it looks like I'm already four months along — what could cause this? Recently I had a threatened miscarriage and spent a week in the hospital; they told me not to go out in the sun and to rest, but my husband and mother-in-law constantly make me do things so I don't lie down at all, saying it's bad to lie like that and I'll get bedsores soon.