Is brownish-redish spotting normal during 4 months of pregnancy?

I normally have brown stains on my panty liner, but last night me and my boyfriend have and I spent the night at his house and when I work up in the morning to go the restroom, I saw I had brownish redish stains on my panty liner. It kinda looked like spotting, it didnt look like the other times I had brown stains. Im going today to the Doctors for a sonogram. Should I let them know about this? Should I worry?