Hey
firstly happy birthday for next thursday!
As it is your birthday do something you really enjoy with company you enjoy. Inviting friends round because you feel you should might make it feel worse because you don't even enjoy their company. Is there someone you particularly enjoy being around? You could do a cinema trip or go out together even if you're not best friends.
If you really do end up spending it alone, plan yourself the best day. You could light the bathroom with candles and put on music and have a huge bubblely bath, watch a trashy romcom, eat your favorite meals- what ever you like doing
Just because you are on your own, it doesnt mean that you are going to have a bad time
Also for present ideas, if you can't think of a present you particularly want, you could ask for a experience present. eg a weekend at the beach, horse riding lessons, boat for a day etc. Sometimes those are the best presents because you remember them for life
Happy birthday and good luck
xxx