losing ammo? without switching weapons

all day today, every time ive went to orbit, through a cut scene, or died ive lost ammo for my special and my heavy, i do not change guns when this happens, i just lose about 1/3 of my ammo everytime, if i die multiple times without using any ammo my heavy will go down to almost 0 when it starts out at 200, im a lvl 30 titan and ive played this game a fair bit, this is never happened to me before so if someone could shed some light on what they think it might be i'd be very appreciative, the only thing different from yesterday, is that i bought the armamentarium exotic chest from xur, everything else is the same.