TMI is this a period

An
Hey guys so I'm on birth control and I'm at the end of my pill pack which means I should be be getting my period in like 3 days but I saw yesterday that there was very light brown when I whiped. I took an antibiotic for a uti and I heard it defects your birth control but when I have sex I use a condom even tho he doesn't pull out, the condom didn't rip tho. Is this my period or is this a pregnancy sign in just really scared and confused because of the antibiotic defect I heard about. I'm not sure if this brown is normal or if it's a birth control period since it's so light.