my cat has been sick lately with just a cold i think... runny nose and eyes, sneezing and coughing here and there. i crushed up half of an anitibiotic and mixed it w water and gave him some in an eye dropper a couple times. he still would drink and eat but he was just conjusted. but now he's been hacking and coughing and coughing up like white foam and i can tell hes even more conjested now and i dont know what it is should i take him to the vet right away in the morning or is he ok if i let him get over it himself like a cold?