urine infection not pregnant?!

So 2 weeks ago I thought I had an implantation bleed which was pink and watery when I wiped, I'm day 12 of my cycle and still no period. Negative pregnancy test and I've a cramping pain in my uterus area, nausea, dizziness, vomiting, exhaustion and mood swings. Trying to conceive me and my husband were convinced we are pregnant! Doctors appointment today told me I'm not pregnant and I have a slight urine infection. Anyone had this? I'm gutted and so confused as to why I have these symptoms?