Overwhelmed at work

I’ve been in my corporate position with this company for 7 years. I’ve been in this particular role for 5 years. Well, we’re a small team of 5 people and we just lost one person and the work has doubled on just me since this happened. The other 2 are seniors on our team and do specific work. The guy that’s equivalent to me is friends with the manager outside of work and only does (2) things out of a million things I do. This guy has been with the company close to 20 years and I think they’re letting him ride out his time until he retires.

My issue is my manager is wanting to give me the workload of the person that left in addition to what I already have on my plate. She mentioned more compensation but I know it’s not going to be what I really feel I should be paid. I want to look externally but I can’t since I’m 8 months pregnant.

I’ve never been in this type of situation please send help!!