primer dimer

[saly]

Please i need the help in my problem:
i design primer but when i made PCR, i found may be formation to
primer dimer under the louding dye but the band of primer dimer under
the negative control ( without RNA ) was small in size than the band
under the sample ( more thick and may be 2 band more closed ). i
belived fond 2 band in sample because the negative control and sample
contain same band in the below but found band upper it in the sample
( may be more thickness )at the same conditions. i tried at 47, 52,
55oC annealing. all tempreature give same result with diffrence in 47
the band under negative control more faint but at 55 the band under
sample more thick and light.
please, i need to know this difference meanse any thing or the
difference in size between the band under control and sample don't
means any thing and the 2 bands are primer dimer only.
Thanks for you