Firstly, whatever you are feeling now, and whatever you decide to do, you have already acheived more than many, many people do in a lifetime. What is more, you are creating great memories that you will look back on with increasing pleasure as the years go by.
Travelling is always a mix of highs and lows, especially when you travel on your own, because it is constantly changing.
I can offer you my experiences, and you can see if you can relate to any of them.
The first time I travelled alone was after a relationship break-up, and at first, it just seemed to highlight the fact that I was now alone. The turning point for me came when I realised that my expectations of the whole 'getting away' thing were too great. The reality was that while I could get away from situations and places, I still had to take myself, and all my feelings and emotions with me. So I changed my expectations.
If this is familiar to you, what I suggest is that you accept that the trip would be like life - up and down - and then see it as a wonderful opportunity to have the time and space to identify the things within yourself that are unsettling you, and work out what you need to be happening / doing etc. for them to bother you less. Then when you do go home, you will be an even stronger, happier you.
Some people find it useful to write down what they need, and then make a mini 'action plan' as to how they can meet each need as they go along.
After your hectic touring schedule, perhaps find somewhere you can slow down a little and just enjoy being there. New Zealand and Australia are fantastic places, and the food and language are much more familiar, so that should help to reduce the anxiety. Why not spend a few days staying in one place, which should mean that you meet a variety of other travellers 'passing through', and see if you find someone that you get on with, that you could travel with for a little while.
Make the effort to talk to people, but make sure you listen to their stories too. Everyone has an interesting story to tell. Also, your experiences may be able to help someone else.
I do agree with all the other blogs too - plus, food wise, I would add avoid anything with ice - especially drinks - , and anything like salad which could have been washed in local water etc, especially in Egypt. However, for most of Europe this should not have been a problem, and I wonder if your tummy problems were partly anxiety. That will get better!
Finally, I think the journal is a great idea, and I would also add the following two suggestions.
1. Get someone to take photos of you in the places you visit, rather than you just taking pictures of the scenery etc. They will be much more interesting to look at, and show people in the future. Ask people you have met to be in the shot with you too.
2. For me, having someone to share experiences with is very special. If you are in a wonderful place, and feeling lonely, think how you would like to share it with someone else, then take the photos, collect the leaflets or do whatever you need to, so that you can share it with people in the future.
I have done this whenever I have travelled, and, in 8 days time , I am about to go travelling again for 4 months with my husband, to take him to many of the places that I first visited alone...and of course to discover lots of new ones too.
Enjoy....your travel now will last a lifetime. XX