Bulldogs World

Clayton who is 15 weeks old  just finished his 2nd round of antibiotics last week.  He sounded congested and my vet put him on clavamox for a week .  That did not seem to clear it up so we then had him on a different round of antibiotics for 2 weeks.  Well last night I noticed blood after he went #2 outside.  I wiped him with a baby wipe and it was a little bloody.  I checked the stool and saw a little blood in it.  He is currently eating Eukanuba puppy lamb and rice and normally has hard stool but this stool was much softer.  Our last vet appointment they had checked his stool and it was fine.  He goes back on Tuesday.  He is acting 100% normal eating drinking playing etc. His breeder had suggested not giving the antibiotics and trying an antihistamine that maybe the congestion was from allergies... I read that blood in stool could be caused from allergies??? has anyone experienced this??? I am at work and my husband told me he just had a normal stool sample with no blood??   Thanks in Advance for your help