Greetings,
On close examination of the mug, it is a nice piece but clearly NOT Wedgwood. The definitive clue is its colour. Wedgwood never used that shade of blue at any time. Wedgwood's blues are both a sapphire and a slate colour. All glass factories have a "recipe" for their glass. There is rarely any cross-over. If you are familiar with the works of particular companies, you will readily recognise their products. You can't confuse Murano with Whitefriars with Wedgwood with Langham, etc, etc.
There are several blue items illustrated in Susan Tobin's book, "Wedgwood Glass". There are also examples of every colour used by Wedgwood. Shapes may be similar, but colours are factory unique.
Enjoy your mug from whatever company it came. I hope you bought a bargain. We all love one.