Unfortunately I suffered a miscarriage I was around 4 weeks..

I had a positive last Tuesday and then started bleeding Tuesday evening, bleeding stopped Friday evening ish, had some Saturday day but didn’t have to wear a pad Saturday evening! And nothing since,

My question is when Can I start having sex? I had sex last night with no protection and a few girls I know are saying you need to wait until you have a period and to use protection while waiting?

Thanks.