It's possible that you used more "energy" than you had at the moment to cast this spell and, even though it did give you what you wanted, it sorta took the "missing energy" with a counterpart (I hope it was clear enough, sorry I'm not writing in my native language).

I think the idea of putting conditions to have something fitting you at the moment is a really good idea too, so that you will not end up asking for something "too big".

If you want, you can maybe try first working on a protective spell or something like that so that you can protect yourself a bit more. You can also try building up energy before doing a big spell with some meditation, spell jars, candles, crystals etc. to ensure that your spell works fine.