Third 3rd trimester - sleep

Hello! I’m at my week 28 (third trimester) and I started to be more sleepyhead than before even compare to first trimester.. There’s once I slept in total of 18 hours in a day.. or normal day can even keep dozing off at day time.. I do sleep a bit late than usual but overall I really sleep too much.. My overall health is good but is this consider normal? My next dr appointment is at 3 weeks later.. Thank you! #pregnancy #advicepls #sleep