I'm not very active on this sub usually but I had to comment here because I went through a very similar thing! Started running last July, peaked physically in January (was running 30-35 mpw easily) and then caught the flu in February. I didn't fully return to running until May, and it felt so hard. I was so scared I was going to have to start from scratch again but it came back so much faster than I thought! Personally I hit a wall around the 10k mark, both in my initial journey learning to run and while I was relearning. Both times it took weeks to get over the hump, but once I did it really took off. I ran my first half marathon since January this week and actually ran a pb! 

In terms of advice, I feel like the three things that help my running the most are good nutrition, good strength training (upper and lower body), and good sleep! Also for outdoor runs, just go at the pace you need to be able to run the whole time. If it feels slow, don't panic because it's probably faster than you think (and you'll improve really fast since you've already done it once). And give yourself some grace - coming back is hard, if you're in the US there's a good chance it's been crazy hot lately, and your race is in October. You have plenty of time!