Or just call up MAC and say you’re concerned.. I’m sure they’ll be happy to check you if you explained to them what happened x
I slipped around the same time and I called the maternity unit and was told they're well cushioned in there with all the fluid, and to just watch out for any bleeding/pain. Also had an anterior placenta, so I did drop an email to my midwife to see if we could have a listen to the heartbeat the next day to settle my worries
Your 20 weeks scan should be coming up soon next week right? If I was you I would take it as easy at possible (no lifting, avoiding walking too much, work from home if possible) until then. Alternatively you can get a private scan this week to check if everything is alright, if that’s feasible financially.