i got a question about a hpt?

okay i took a hpt last nite, it was a dollar one. and it showed negative with one line in the control line, but after about 5 to 10 minutes i was still a negative. but the negative it was clear white and just the negative sign, i took one this morning, and it was still negative, i used my first morning urine. but after a couple of minute, i wasnt such a clear white with a negative it was shill yellowish brown, and it looked like it was trying to show another line, what does this mean, or has anyone else had this same problem looking a hpt after you know its been awhile? any opinions plz