Brown streaks on underwear, 24 weeks pregnant

I just got back home from being on the road for 11 hours, we were driving back from Ohio. I noticed that there are streaks of brown blood on my underwear. I also have slight pain on my left side. I haven't had any bleeding or discharge this whole pregnancy so it completely threw me off. I was basically just sitting the entire day today in the car apart from the occasional restroom breaks.

Has this happened to anyone else?

I did call my doctor and she asked me to monitor baby's movements, but I don't really feel her move even after drinking cold water, it's been half an hr, or I feel like I feel her move but it's very very weak and hard to decipher so I am very confused and scared 😕