Need advice..

I am currently around 8 weeks pregnant and am waiting for my first obgyn on Tuesday but have a queation... the last two times my boyfriend and I have had sex bleed after wards... not right after but like the next day.... it's not gushing and I have no cramping but when I wipe there is some, I pee and theres some in the toilet.... we had sex last night and I just went to the bathroom and there was blood on my underwear... prolly a spot the size of a half dollar and some when I wiped... I have never experienced this and this will be my 4th child... should i go to er or just bring it up to the Dr next week?