Pregnancy and allergic reactions?

I think I may be pregnant (I have all the symptoms but the test was negative, I'm waiting a week to test again) and I've been having allergic reactions. I recently determined that the reactions were to a chapstick that I've been using for years. I then bought a new brand and it worked for a few days then, I reacted to that, too. My lips are severly chapped (which I've never really had much of a problem with before--another symptom of pregnancy?) so I need to use something on my lips. Is it common to have allergic reactions after getting pregnant to something that has been used a lot before pregnancy?

Extra details: If I am pregnant, I'm about 5 weeks along. My reactions consisted of swollen lips and feet and itchy feeling all over my body.

If anyone can help, I'd really appreciate it! Thanks and God bless!