Worried... I know this is probably gross but I'm very scared

Last night my boyfriend and I decided to finally be intimate with each other. Shortly after I was spotting then a big blood spot was discovered in my under wears. Shortly after that I started to feel pressure in my pelvis. It was mild pressure so I got the heating pad. I woke up this morning with a brown discharge and I was so confused. Now I'm bleeding again but it's sort of brown in it. I'm worried if this a miscarriage or am I bleeding because of ax.