Depression, pregnancy or both?

So I’m 8 months pregnant and have major depression disorder. This whole pregnancy has been hard because I’ve been super tired through most of it, especially this last month. It’s hard for me to tell if this exhaustion I’m feeling is from my depression my pregnancy or both. All I know is it’s bad. Most days I just want to sleep all day. Even if I sleep good the night before by the time the day is half over I feel like I’ve run a marathon and am exhausted. Anyone else dealing with both depression and pregnancy? How do you manage your sleep schedule so you don’t feel as tired?