Hi Rudy, it looks like you're currently trying to sweep the shape kind of "in place" directly.

It is possible to do that, but somewhat more difficult - here I will show you a different approach of combining more simple shapes, I'm not sure if it will be exactly what you need but it will make for a clean shell though.

To start with, I drew a profile curve in the front view:



I made sure there that the 2 ending points on each side are horizontal or vertical with one another to make sure the next step will be smoothly rounded.

Then select that profile, and run Construct / Revolve, and pick this as the revolve axis:



That creates this base form:



Now switch to the Top view, and draw a circle:



Select the base form, and run Construct / Boolean / Difference, and select the circle as the cutting object. That will leave you with this shape:



Now it is probably a good idea to shell it first, go to the under-side of the object and select that bottom face, then you can shell it:



After that you can select this edge:



And fillet:





- Michael