26 Weeks with spotting(no picture)

I've been admitted for contractions already and they stopped so I was sent home. Last night after work I was having the worst period like cramps I have experienced, I just laid down and went to sleep since I had work this morning. While at work I got a cramp so bad I had to sit down for a bit it just felt like hunger pains. I got off at 3, came home to change and there's spots of blood in my underwear( I went to the bathroom in the middle of my shift and nothing was there) I wiped and no blood. I'm waiting on my doctor to call me back and Google definitely isn't my friend. Any advice?