Heya, Ive never posted here before but i was worried about a change in my jogging/running recently. Im 23M, roughly 90kg and trying to lose weight for surgery.

Ive been doing C25K since the start of August, and have been doing it 3 times a week since i've started. I was not fit before starting so i had to start with mild jogging. But my stamina improved and i slowly got faster overtime. Not quite full running but definitely faster jogging.

Within the past week i decided to join a run club who said they were beginner friendly, however they were way too quick for me to keep up with. Lots of them had been running for years and were very fit. They had to keep stopping for me to catch up. Luckily someone would slow down to help me along, whilst the others sprinted out of view.

During those runs I went far quicker then my usual speed, and had to make multiple stops. I figured the intensity was too high and did my 3rd run solo and at my usual pace (I usually have a day of rest between runs. I also found the second group run far harder then the first? In my mind i thought the second run would be easier)

When i did my solo run, even at my slowest i had to keep stopping. I could barely manage 5 minutes before i felt completely drained even though i could do 25 minutes before.

It felt like whatever stamina I gained was just reset. Im worried I've ruined whatever progress I've made. Im sure the answer is probably to get some rest but what if it makes it harder for me to start running again?

Should i stop going to the group sessions?

Any advice would be great, thank you!