Pregnancy symoptoms before period

My wife and I did it twice in few days later after her last period. Then did it again twice during ovulation days. My wife had nausea, dizzy, lower back pain and stomach pain before her next period is due in 1 week. she feels like vomiting but anything never come out from her mouth after trying to vomit it out. She says she never experience it before. Usually, nausea starts in 4-6 weeks after miss period. but she got it before she miss period. Is she pregnant or did she eat wrong food? I took her to TCM yesterday to get medicine to relieve her nausea.