12 weeks, strong symptoms are back

I'm 12w4d today (measuring "on time" per LMP and scans). About 10w6d I started feeling much less nauseous. Had a scan on 11w1d that showed normal fetus/development to that point.

A few days ago I suddenly got sick and have been throwing up again. Also getting bad headaches and past couple of nights I've woken up like 4 times per nights from INSANE vivid dreams which was one of my early pregnancy symptoms.

The nausea fortunately is coming and going - I think it may be actual heartburn because it is coming with some regurgitation and acid reflux and Tums did make it go away. I also still have breast tenderness and pains shooting through my boobs/nipples at times lol.

I just read everywhere that most women get "better" now and I seemingly got better and then worse. Is this "normal"? I have a scan tomorrow and getting nervous.

Thanks everyone