Air carrier Captain reported a temporary loss of aircraft control during a low altitude go-around when they encountered a possible microburst. Captain regained aircraft control and returned to complete the approach.

Narrative

Was originally being vectored around weather for an approach to Runway XXR at ZZZ. Several thunderstorms were in the vicinity of the airport and on the approach corridor to Runway XXR. We had deviated south of course and the airport due to a line of weather. We proceeded south of the airport until we were east of the weather. At this point we began receiving vectors around the weather from Approach Control. As we were vectored for an approach to XXR; the winds changed and began to favor Runway XL. ZZZ Approach Control then began vectoring us around the thunderstorms to proceed for a visual approach to Runway XL. Upon turning downwind to base; we got the runway in sight. There were low broken cloud layers around the airport but we were able to maintain visual contact with the runway and were cleared for the visual approach. We began configuring on the base leg; but it became difficult to slow down in the convective conditions. We used the speed brakes in an unsuccessful attempt to help slow the airplane down. Upon base leg to final it became apparent that we would not become stable to land; accompanied by a strong gusty crosswind (reported as direct crosswind of 14 gusting to 30 if memory serves me); so I decided to execute a go around at approximately 500 ft AGL. Upon announcing go around and engaging the GA switches; the aircraft began to encounter severe turbulence. At this point I'm uncertain if I fully retracted the spoilers as I executed the go around. Regardless; the airplane became very difficult to prevent from entering the overspeed range. We received no wind shear caution or warning; but the airplane became momentarily very difficult to control and difficult if not impossible to prevent from an overspeed condition in what felt like a downdraft. We were given instructions to climb to 4000 MSL; but were unable to level at 4000 without a significant overspeed on the airplane as our speed was difficult to control between 245 and 260 or so. The First Officer communicated to ATC that we would be unable to maintain 4000 feet so they subsequently gave us a block altitude of 5000 - 120000 MSL. We were able to get everything back under control at approximately 5000 MSL and were then given delay vectors away from the weather and asked of our intentions. We flew delay vectors momentarily to the southwest (extended wide downwind) while talking through the decision-making process. We still had about 2000 lbs of bingo fuel and the weather began to move off the field as we were vectored. We came back around as the weather had improved (winds were now almost straight down the runway and not as gusty) and attempted another approach with much better weather conditions this time that led to a normal approach (winds straight down the runway now at 12 knots) and landing.Cause: Thunderstorms in the area with possible downdraft/microburst in the vicinity of the airport.Suggestions: Could have been prevented by more delay vectors or possible northern vectors with holding until weather was clear of the field. At the time; however; thunderstorm activity was unpredictable. Still would have been better to hold for the weather rather than accepting vectors to try to make it in to the field ahead of the weather.