I had Covid 4 times last year despite being fully vaccinated! The first time my daughter and I both got it. She did tests as she needed to know if she could go to work and all were negative. As we both had same symptoms and had been together looking after my grandson while his parents had a weekend away we assumed we had toddler lurgy as grandson had been very snotty all weekend, so I didn't test. I even did my normal shift delivering for the foodbank. Then I wanted to go out socially and DD said I shouldn't as I was clearly still unwell, so I tested and got a very bright positive line! I did feel bad that I'd been out and seen people, though all contact had been brief.
The remaining times when I caught it, I tested positive but the lines were very faint, so I assume my viral load was lower - probably some immunity from having it before. We did order groceries online one of the times but one time I chose to go shopping while still positive (after about 5 days of isolating) but went at a quiet time, wore a mask, and just grabbed a few essentials, paid at the self service till and left very quickly. I don't feel guilty as I know lots of people don't test at all and many people are asymptomatic so I just did my best to keep the risk to a minimum. If I feel unwell I try not to go out socially, even if it is just a cold, as I have some very elderly friends who are quite vulnerable.