What could it be?!?!

Samantha • Me and my boyfriend have been together for almost 8 years we have 2 kids together and ttc #3 after a MC 🙏🏻👶💗💚💙
Could this be early pregnancy symptoms I have had a nasty tast/felling in my mouth I keep brushing my teeth but it's not helping my back is killing me I'm having pain in my lower abdomen when ever I sit down to hard or sneeze or anything like that and pain whenever I have sex not sheer if I'm reading to much in to it HELP!!