Could my three month old have a cold?

Alright, my three month old daughter has always been a very good baby. She only ever cries when she is hungry, and tends to fuss a tiny bit when she's tired. Lately however she seems very irritable. She doesn't have hour long crying fits as if she were colicky, but for about five minutes or so you have to keep trying different things with her to make her happy: standing her up, sitting her down, laying her down, holding her to your chest while sitting, holding her to your chest while standing and walking, putting her in her swing, putting her in her walker, etc. She has been drooling quite a bit, and sucking on her fingers, sometimes crying when she does, I figured that she was teething early. However she is also having more snot and boogers than she's had before, and seems to be choking or gargling a lot of mucus or drool. She's also seeming to eat a lot more while excreting a lot less, and she's sleeping a lot more than usual. Does she perhaps have a cold or something else? There's been minimal coughing, same as she's ever had, just one or two little coughs now and then to clear her throat.