Hola mis amigos.
Stay in the moment with Spanish. Do not give up. (I'm talking to myself as well). When you are speaking to a speaker that understands Spanish and English, it is easy to default to English especially when you haven't learned how to say the words (YET!) in Spanish. You can mix Spanish and English to stay in that conversational moment. Yo no sé pero I lost mis llaves. I have no clue of where they could be. No tengo idea. Tengo fe que las encontraré.
I had a moment yesterday where I could not recall the words I wanted to say to my Spanish speaking client (who also understood English). It ended up being okay porque I came right back into the moment with Spanish. And do not worry. Native Spanish speakers who speak English do it too. That's why we have Spanglish! :)