Pleased to hear that you went and enjoyed parkrun, Kate. One of the bset things about parkrun, in my opinion, is the community spirit and the fact that others of all levels are encouraged. We all start somewhere!
I'm currently coming back from a lengthy injury and receive so much support from other parkrunners. It definitely helps to keep you going!
If they're not full length maybe you could put them under the shoe insole for a bit. I did blister badly with mine when I started running and was advised to maybe try 10 mins, then take them out, then build it up.
Build up the time with them. It takes a good while for you feet to get used to them. When I had orthotics previously I was advised to wear them for walking initially and ease into running. Take it easy & you'll get there.
Silk liner gloves (you can get them in outdoor shops are good). I often find that I can run without gloves but it's the change from outdoors to indoors that triggers it due to the temperature shift, so try putting gloves on as soon as you get inside or into the car & that might help to begin.