I can't stay off the toilet. Ugh.

I am 37w1d and have had severe diarrhea since yesterday. I was having contractions yesterday along with feeling a lot of pressure but the contractions ended up going away. Tonight I cannot stay off of the toilet and I keep getting these weird sharp pains in my vaginal area. This is my third baby (I just had one in January) but I have never experienced any of this with my other two. Has anyone else experienced this before & is this a sign that labor is near?