What's wrong with my temperature?

I am recovering from a cold. I just got back from the doctors an hour ago and they told me I had no fever and just to keep taking my cold medicine. A few minutes before I went to the doctors my temp was 99.2. Though, when I got home from the doctors I was at 99.2 still. I ignored it but then I took a warm bath which I thought was okay since I don't have a fever. I take my temp right after I get out and it says 99.8 (I know it would raise after I get our of warm water) but then I washed my face for 10-15 seconds with cold water and took my temp right after which jumped to 100.2! Maybe my thermometer is wrong? Same thing happened at school on Thursday. Nurse took my temperature and it was 98.8 but when I got sent home for puking in school, it raised to 99.5. I was fever free for 2 days. Do you think it's because today it was really hot outside? My face feels kind of warm but when I touch it it's fine. What could this be? Should I listen to my doctor who said I'm fine or should I listen to my thermometer? Also my parents said my temp is normal. I don't know what to believe. Thanks