27 weeks pregnant with first touch of nausea?

Morning this is my second pregnancy and my first a boy went so smoothly no problems this pregnancy a girl I've been diagnosed with SPD sciatica and only now at 27 I have started feeling sick all this week like a constant uneasy feeling above my bump I am not hungry I've never had morning sickness in either pregnancy can it just come on at this point and what can I do to ease it I've obviously got my toddler to look after but feel so woosy thanks in advance x