Weird pregnancy symptoms before BFP

I had sex once during my fertile window. Now I’m having weird symptoms such as my taste and sense of smell comes and goes, the smell of cigarettes now makes me feel sick to my stomach. I am a smoker and now the taste of it as well makes my stomach do front flips 🤢 My boyfriend also have been complaining of backaches. It’s too early to test BUT these things are way out of the norm. PLEASE HELP