Dimetap at 32 weeks! HELP :(

The last 3 days I've had the worst cold ever and I haven't been able to sleep even more than usual because my nose is completely clogged. So I wake up every half hour with sand mouth and my lips cracked open. So last night I was half dead and got up for the 900th time to get water and grabbed done dimetap and took a swig. Right after I swallowed I was like oh shit what am I doing. I looked it up and it can cause birth defects or something in the third trimester and could pass to baby when breast feeding. Should I call my doctor or is a swig even enough to worry?