Confirmed pregnancy after depo shot????

Hi all,

Just looking for some advise. I had the depo shot in April and was due next in 17th July. Me and my partner decided we want a baby.. I then had a bleed from 24th July to 31st July. However it was so light only noticed when I wiped when I went toilet and during sex and would also use one panty liner in the day in case which only had few drips but mainly brownish blood. If I classed this as a period it would mean Im most fertile between now and Wednesday next week.. bare in mind I was having sex during bleeding stage as it was so light barely bothered us. pregnancy test today was negative however may be to early, and I took ovulation text which showed faint line.. Now I'm having odd cramps and loose bowl movements. Any advise on what's going on with my body?