Could I be pregnant or just stressed??

Okay ladies. So my period is two days late. I lost a baby three years ago in my second trimester and haven't really TTC since that happened. Until about three months ago. I say three because I was given the depo (first time) in February and I hated what it did to my body. I never went back. It is now July and my last couple periods have been regular. A week or so I experienced what I think is implantation bleeding (brownish discharge for a day and a half.) I'm not 100% sure though because it's been so long. I tested negative a week before my missed period, two days before and today makes two days after. ALL NEGATIVE! 🙁 I have symptoms of pregnancy. Feels like morning sickness all day but when I eat it's worse. I just can't hardly stand the smell of anything. I feel so tired and my back is killing me! And you know that feeling you get, where you just know and you see signs everywhere (i.e. Double rainbows, literal pregnancy signs on the highway, at the doctors for a check up there was a parent magazine) this could all just be coincidence!! The reason I asked about stress is that I have a very stressful job. I work in a dog grooming salon and things can get pretty hectic. I lift 50-60 lb dogs every day and I'm worried if I am pregnant that it would cause me to miscarry. I've heard a lot of people say that they tested negative even up to TWO weeks after their missed period. I just really need some advice. :(