Could I be pregnant?

I had my implant removed at the end of march. I didn't have a period in april and then I had a period in may and got pregnant that cycle. I had a miscarriage in june/July at about 7 weeks. It was a bit complicated because it didn't all come away all together we thought it was over and I went back to work but 2 weeks later I was bleeding again and finally passed it all and scan was then clear. We waited til after I had one period before having unprotected sex. That period was a bit confusing. I started inputting data on my app and ended up changing it because I thought it was my period but it more like spotting for the first days so in the end I counted my period as the last 4 days which were actually like a proper period flow so the dates of my period are a bit confusing in a way but I've just counted it from the 20th August. According to that my period is due in 4 days (17th September). I feel soooo pregnant and beginning to worry that I'm doing it to myself and setting myself up for failure. All the tests have done are negative. My boobs seem swollen and my nipples are really sensitive. I am really bloated and constipated. My mouth tastes weird and I can't seem to drink enough always thirsty. Peeing all the time. I do feel a bit nauseas but not like I could actually be sick. Earlier I felt a bit woozy and weak. I do feel twinges in my stomach but nothing ridiculously painful. I'm exhausted and keep getting headaches. Am I just going insane?!?! Please help. Many thanks