Congrats on your pregnancy, mama! Ito talaga ang first trimester experience for most of us, yung nausea and back pain ay super normal, and honestly ang bedrotting ay part ng adjustment kasi ang body mo ay nag-aadapt sa lahat ng hormonal changes. Pero kasi you were so active before, I get na weird ang feeling ng pagiging stationary, pero don't guilt yourself, this is temporary lang and your body really needs the rest right now, lalo na if nag-start na ang morning sickness.
Best advice? Take it easy but listen to your OB din because sometimes gentle movement like short walks or prenatal stretches can actually help, pero since you just found out and bagong symptoms pa, better check with your doctor first about what's safe for you specifically, para walang worry at alam mo exactly kung ano pwede mo gawin. In the meantime, stay hydrated, eat small frequent meals if kaya mo, and be kind to yourself, this phase won't last forever!