22 weeks horrible lower back pain..

for about the past hour my back pain has gotten increasing worse. I haven’t had THAT bad of back pain at all until today. I didn’t do much today.. Laying down doesn’t relive it. Laying flat makes it feel like a lingering type of pain then when I stand up it’s pretty intense. My stomach is hard and feels a little tight, but I don’t think any contractions. It’s kind of making me feel nauseous. I’m also a little paranoid of preterm labor etc so .. anyone else have this? I took some Tylenol about 15 min ago, I’m about to take a bath to see if it helps. Yesterday, (TMI) I was super hot and had diarrhea. I’ve had a head cold for the past week or so too. Coughing and sneezing a lot. Any advice or anyone that can relate? Thanks