you can use the holy water to bless your room, it’s blessed itself, so no matter who uses it, it will bless.
i would also suggest,** if you’re able, get a Saint Benedict medal, which you can get just as a medal, or you can get it in a cross, and then ask your priest if he can do the actual Saint Benedict blessing on it, not just a regular blessing, **and then keep it in your room, or even hold it while you sleep.
you can get the medal here, and also read what it’s all about -
olrl.org/sacramental/benedictmedal.shtml
this is the cross i have -
catholicstore.com/8-22BlackWoodSt.aspx
but there are cheaper ones if that’s too expensive…i actually got mine for $20, but the price has since gone up.
you can also pray for help with your bad dreams, ask your Guardian Angel to watch over you when you sleep and protect you from bad dreams, or pray for the Holy Souls in Purgatory, say some Hail Mary’s for them, or say the St. Gertrude prayer, which is said to release 1,000 souls from Purgatory each time it is said -
“Eternal Father, I offer Thee the most Precious Blood of Thy Divine Son Jesus, in union with the masses said throughout the world today, for all the Holy Souls in Purgatory, for sinners everywhere, for sinners in the Universal Church, those in my own home and within my family. Amen.” and ask them to pray for you in return.
and of course Our Blessed Mother is always best to go too, ask her to spread her mantel over you before you go to sleep, and ask her to send her angels down to watch over you.
after moving into my new house a couple years ago, i was all of a sudden having rather frightening dreams, even waking up to feeling like i was being pulled off my bed…i honestly can’t say what it really was, but after i finally got around to getting my house blessed, the bad dreams stopped, and i had much more peaceful nights…so perhaps, if you haven’t already done it, that might be what you need.
alright, so i hope this helps, take care.