Infant fever

My five month old has a 100 degree fever granted it’s being taken with a forehead thermometer because I can’t find the other one. However, I’ve had the flu and haven’t been able to stay away as much as I’d like because we can’t afford for anyone to be miss work much less both of us. It was 99.9 earlier and now 100 however I’ve taken my temperature several times within a couple minutes and it came up pretty different numbers so I know it’s not too accurate. Should I wait for an appointment tomorrow or take her to get checked out tonight?

I did call the doctor about 99.9 and she said if it stays the same then to bring her in tomorrow or if it goes up to go to the ER or an after hours place.