discharge question. close to labor?

I'm a first time mom and not sure what to expect. I'm in the third trimester and my baby is head down. I've been getting pains down in my vagina area and leaking a yellow clearish watery discharge for a couple weeks. Today I decided to start wearing pantiliners because I'm over changing my underwear so often. I just went to the bathroom and noticed there's a pink bloody tinge to it? Is this normal at this stage? And does this indicate labor is coming, or does it just happen by third trimester?