Being sick = supply tanking

This is my first time posting on this board as I have never had any problems BFing and have always had a great supply. I've had a cold for the past nearly 3 weeks. I haven't been taking any medicine obviously. I've been to the doctor and it's not anything more. I also have a little bit of allergies going on from BILs darn cat.

The past few days, DD seems to be more hungry. I put her to the breast and she sucks for a minute and then gets frustrated until I have my letdown. Then will suck for a minute after that before getting upset again. Then I end up switching her to the other side. She is usually upset after she is done on that side too. She gets solids twice a day is BFing every 2-3 hours on demand. For the past week or so, she has been STTN. She also seems to have enough wet diapers, but seems to be still hungry. She is happy throughout the day for the most part.

 Tonight, she woke up an hour after we put her down and I had one bag of milk in the freezer DH gave her which was like 5 oz. She drank it all. We're having a hard time getting her back down now.

I don't know if it's because I'm sick that my supply has decreased or if DD is going through a growth spurt or both. I really don't want to have to give formula, but of course I will if it comes down to it. I have been drinking lots of water and trying to eat more. I just bought some mother's milk tea. What else can I do? Has anyone else been through this and gotten their supply back?

TIA