Digestive issues this week - vial contamination?

I have been on 5mg subq E injections for about 4 months now. Since late last weekend I have been having various levels of intestinal issues (bloating/cramping after eating, gas, looseness etc) that sometimes has made it difficult to sleep. I originally thought that I had eaten bad food or it was a reaction to ongoing stress/tiredness as often I have these issues when travelling etc, but it has been happening with reduced stress and gentle foods as well. Finally today it seems better, but I am scheduled to inject my E tomorrow and with everything going on with my body I am worn out and suddenly paranoid.

1. Could it be a sign of infection and that my vial is compromised? I thought that infections are mostly localised in the tissue themselves, but I was reading that colitis could be caused by infection? Although that is more likely to be infected food/water, isn't it... Am I just being paranoid as a result of all the stress of it?

I have experienced no fever/high temperature, or swelling/redness at my recent injection sites, and feel fine apart from the digestive issues. My vial was from V@nna, made probably April 2024 but sealed until July 2025, and no sign of particles/discolouration are visible.

2. Should I switch over to my backup vial (also same age and from V@nna)? I am planning to do so currently since at least it will relieve my anxiety about the original vial and potential contamination.

I know I should go see a doctor but I have always considered it a last resort with how hateful the NHS is to us, so only wanted to do so if it was medically vital. Especially if I have to present to them with "I'm trans and taking DIY and it might have made me ill".

In regards to my E levels I am arranging a blood test right now to determine my levels, but have resorted to ordering a home test due to not feeling well enough to travel to a clinic recently. At least it will give me an approximate reading of my levels.