No your prayers are valid. You didn’t know so that’s ok. The wudhu that you did was simply void.
But from now on, after Ghusl al-Janabah, don’t do wudhu. You have full purity with it. Ghusl al-Jum’a also gives you purity according to Ayatollah Sistani, but you can still do wudhu after it (it’s recommended).