So I am getting ready for a trip out of town and my mind totally blanked on giving Monty his heartworm pill yesterday. I just dropped him off for the next four days to spend the weekend with his dad while I am at a wedding. Is it too late to give him the missed pill on Sunday or do I need to call the vet near his daddy and have a dose on stand by for him to pick up to give to him? I can't believe I forgot and now I feel like the worst mommy..